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1. MASCOT’s in situ analysis of asteroid Ryugu in the context of regolith samples and remote sensing data returned by Hayabusa2

Author: Katharina Otto, Tra-Mi Ho, Stephan Ulamec, Jean-Pierre Bibring, Jens Biele, Matthias Grott, Maximilian Hamm, David Hercik, Ralf Jaumann, Masahiko Sato, Stefan E. Schröder, Satoshi Tanaka, Ulrich Auster, Kohei Kitazato, Jörg Knollenberg, Aurelie Moussi, Tomoki Nakamura, Tatsuaki Okada, Cedric Pilorget, Nicole Schmitz, Seiji Sugita, Koji Wada, and Hikaru Yabuta
Subjects: Asteroid Ryugu, In situ analyses, Asteroid sample return, Multi-scale analysis, Asteroid regolith properties, Asteroid regolith, Geography. Anthropology. Recreation, Geodesy, QB275-343, Geology, QE1-996.5
Abstract: Abstract The Hayabusa2 mission provided a unique data set of asteroid Ryugu that covers a wide range of spatial scale from the orbiter remote sensing instruments to the returned samples. The MASCOT lander that was delivered onto the surface of Ryugu aimed to provide context for these data sets by producing in situ data collected by a camera (MasCam), a radiometer (MARA), a magnetometer (MasMag) and a spectrometer (MicrOmega). In this work, we evaluate the success of MASCOT as an integrated lander to bridge the gap between orbiter and returned sample analysis. We find that MASCOT’s measurements and derivatives thereof, including the rock morphology, colour in the visible wavelengths, possible meteorite analogue, density, and porosity of the rock at the landing site are in good agreement with those of the orbiter and the returned samples. However, it also provides information on the spatial scale (sub-millimetres to centimetres) at which some physical properties such as the thermal inertia and reflectance undergo scale-dependent changes. Some of the in situ observations such as the presence of clast/inclusions in rocks and the absence of fine particles at the landing site was uniquely identified by MASCOT. Thus, we conclude that the delivery of an in situ instrument like MASCOT provides a valuable data set that complements and provides context for remote sensing and returned sample analyses. Graphical Abstract
Published: 2023
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2. The MMX rover: performing in situ surface investigations on Phobos

Author: Patrick Michel, Stephan Ulamec, Ute Böttger, Matthias Grott, Naomi Murdoch, Pierre Vernazza, Cecily Sunday, Yun Zhang, Rudy Valette, Romain Castellani, Jens Biele, Simon Tardivel, Olivier Groussin, Laurent Jorda, Jörg Knollenberg, Jan Thimo Grundmann, Denis Arrat, Gabriel Pont, Stephane Mary, Markus Grebenstein, Hirdy Miyamoto, Tomoki Nakamura, Koji Wada, Kent Yoshikawa, and Kiyoshi Kuramoto
Subjects: Camera, Numerical modelling, Phobos, Radiometer, Raman spectrometer, Regolith, Geography. Anthropology. Recreation, Geodesy, QB275-343, Geology, QE1-996.5
Abstract: Abstract The Japanese MMX sample return mission to Phobos by JAXA will carry a rover developed by CNES and DLR that will be deployed on Phobos to perform in situ analysis of the Martian moon’s surface properties. Past images of the surface of Phobos show that it is covered by a layer of regolith. However, the mechanical and compositional properties of this regolith are poorly constrained. In particular, from current remote images, very little is known regarding the particle sizes, their chemical composition, the packing density of the regolith as well as other parameters such as friction and cohesion that influence surface dynamics. Understanding the properties and dynamics of the regolith in the low-gravity environment of Phobos is important to trace back its history and surface evolution. Moreover, this information is also important to support the interpretation of data obtained by instruments onboard the main MMX spacecraft, and to minimize the risks involved in the spacecraft sampling operations. The instruments onboard the Rover are a Raman spectrometer (RAX), an infrared radiometer (miniRad), two forward-looking cameras for navigation and science purposes (NavCams), and two cameras observing the interactions of regolith and the rover wheels (WheelCams). The Rover will be deployed before the MMX spacecraft samples Phobos’ surface and will be the first rover to drive on the surface of a Martian moon and in a very low gravity environment. Graphic Abstract
Published: 2022
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3. Mechanical Properties of Cometary Surfaces

Author: Jens Biele, Jean-Baptiste Vincent, and Jörg Knollenberg
Subjects: comets, mechanical properties, strength, density, porosity, Churyumov–Gerasimenko, Elementary particle physics, QC793-793.5
Abstract: Mechanical properties, in particular, strength (tensile, shear, compressive) and porosity, are important parameters for understanding the evolution and activity of comets. However, they are notoriously difficult to measure. Unfortunately, neither Deep Impact nor other comet observations prior to Rosetta provided firm data on the strength of cometary material. This changed with the Rosetta mission and its detailed close observation data and with the landing(s) of Philae in 2014. There are already many articles and reviews in the literature that derive or compile many different strength values from various Rosetta and Philae data. In this paper, we attempt to provide an overview of the available direct and indirect data; we focus on comet Churyumov–Gerasimenko/67P but include a discussion on the Deep Impact strength results. As a prerequisite, we start by giving precise definitions of ‘strength’, discuss soil mechanics based on the Mohr–Coulomb ‘law’ of micro-gravity, and discuss bulk density and porosity, sintering, and the physics of the strength of a cohesive granular medium. We proceed by discussing the scaling of strength with the size and strain rate, which is needed to understand the observational data. We show how measured elastic properties and thermal (conductivity) data can be correlated with strength. Finally, a singular very high strength value is reviewed as well as some particularly small-strength values inferred from the bouncing motion of Philae, data from its collisions with the surface of the comet, and scratch marks it left, allegedly, on the surface close to its final resting site. The synthesis is presented as an overview figure of the tensile and compressive strength of cometary matter as a function of the size scale; conclusions about the size dependence and apparent natural variability of strength are drawn.
Published: 2022
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4. In Situ Regolith Seismic Velocity Measurement at the InSight Landing Site on Mars

Author: Nienke Brinkman, Cédric Schmelzbach, David Sollberger, Jan ten Pierick, Pascal Edme, Thomas Haag, Sharon Kedar, Troy Hudson, Fredrik Andersson, Martin van Driel, Simon Stähler, Tobias Nicollier, Johan Robertsson, Domenico Giardini, Tilman Spohn, Christian Krause, Matthias Grott, Jörg Knollenberg, Ken Hurst, Ludovic Rochas, Julien Vallade, Steve Blandin, Philippe Lognonné, W. Tom Pike, and W. Bruce Banerdt
Published: 2022
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5. Science objectives of the MMX rover

Author: Stephan Ulamec, Patrick Michel, Matthias Grott, Ute Böttger, Susanne Schröder, Heinz-Wilhelm Hübers, Yuichiro Cho, Fernando Rull, Naomi Murdoch, Pierre Vernazza, Olga Prieto-Ballesteros, Jens Biele, Simon Tardivel, Denis Arrat, Till Hagelschuer, Jörg Knollenberg, Damien Vivet, Cecily Sunday, Laurent Jorda, Olivier Groussin, Colas Robin, and Hirdy Miyamoto
Subjects: Phobos, Martian moons eXploration MMX, Rover, Aerospace Engineering
Published: 2023
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6. Design details of the HP3 mole onboard the InSight mission

Author: Olaf, Krömer, Marco, Scharringhausen, Fittock, Mark, Georgios, Tsakyridis, Torben, Wippermann, Lars, Witte, Matthias, Grott, Jörg, Knollenberg, Tilman, Spohn, Christian, Krause, Troy Lee, Hudson, Roy, Lichtenheldt, Jerzy, Grygorczuk, and Lukasz, Wisniewski
Published: 2019
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7. Soil Thermophysical Properties Near the InSight Lander Derived From 50 Sols of Radiometer Measurements

Author: Sylvain Piqueux, Nils Müller, Matthias Grott, Matthew Siegler, Ehouarn Millour, Francois Forget, Mark Lemmon, Matthew Golombek, Nathan Williams, John Grant, Nicholas Warner, Veronique Ansan, Ingrid Daubar, Jörg Knollenberg, Justin Maki, Aymeric Spiga, Don Banfield, Tilman Spohn, Susan Smrekar, and Bruce Banerdt
Published: 2021
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8. Calibration of the Heat Flow and Physical Properties Package (HP) for the InSight Mars Mission

Author: T. Spohn, Marco Scharringhausen, Sue Smrekar, Torben Wippermann, William B. Banerdt, Matthias Grott, Jörg Knollenberg, Troy L. Hudson, and Christian Krause
Subjects: Materials science, Calibration (statistics), business.industry, General Earth and Planetary Sciences, Mars Exploration Program, Environmental Science (miscellaneous), Aerospace engineering, business, Heat flow
Published: 2019
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9. Soil Thermophysical Properties Near the InSight Lander Derived From 50 Sols of Radiometer Measurements

Author: John A. Grant, Veronique Ansan, Nicholas H. Warner, Matthew P. Golombek, Bruce Banerdt, Nils Müller, Justin N. Maki, Matthias Grott, Tilman Spohn, Mark T. Lemmon, Susan Smrekar, Nathan R. Williams, François Forget, Ehouarn Millour, Ingrid Daubar, Matthew A. Siegler, Aymeric Spiga, Don Banfield, Jörg Knollenberg, Sylvain Piqueux, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Planetary Science Institute [Tucson] (PSI), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), and Texas A&M University [College Station]
Subjects: Radiometer, 010504 meteorology & atmospheric sciences, Temperature, Mars, Mars Exploration Program, 01 natural sciences, Duricrust, Soil, Geophysics, Space and Planetary Science, Geochemistry and Petrology, [SDU]Sciences of the Universe [physics], 0103 physical sciences, Thermophysics, Earth and Planetary Sciences (miscellaneous), 010303 astronomy & astrophysics, Geology, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Remote sensing, InSight
Abstract: Measurements from the InSight lander radiometer acquired after landing are used to characterize the thermophysical properties of the Martian soil in Homestead hollow. This data set is unique as it stems from a high measurement cadence fixed platform studying a simple well-characterized surface, and it benefits from the environmental characterization provided by other instruments. We focus on observations acquired before the arrival of a regional dust storm (near Sol 50), on the furthest observed patch of soil (i.e., ∼3.5 m away from the edge of the lander deck) where temperatures are least impacted by the presence of the lander and where the soil has been least disrupted during landing. Diurnal temperature cycles are fit using a homogenous soil configuration with a thermal inertia of 183 ± 25 J m
Published: 2021
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10. The data format of the MErcury Radiometer and Thermal Infrared Spectrometer (MERTIS) onboard BepiColombo

Author: Rainer Berlin, Harald Hiesinger, Mario D'Amore, Thomas Säuberlich, Jörn Helbert, Alessandro Maturilli, Jörg Knollenberg, and Gisbert Peter
Subjects: BepiColombo, chemistry.chemical_element, Venus, NASA Deep Space Network, Spectrometer, law.invention, Orbiter, law, Thermal, Calibration, Remote sensing, Radiometer, MERTIS, Spacecraft, biology, business.industry, biology.organism_classification, Mercury (element), MErcury, chemistry, data, Environmental science, business, Infrared
Abstract: The MErcury Radiometer and Thermal Infrared Spectrometer (MERTIS) is an instrument to study the mineralogy and temperature distribution of Mercury’s surface in unprecedented detail. MERTIS was proposed in 2003 as payload of the Mercury Planetary Orbiter spacecraft of ESA-JAXA BepiColombo mission and will reach Mercury in 2025. MERTIS will map the whole surface at 500 m scale, combining a push-broom IR grating spectrometer (TIS) with a radiometer (TIR) sharing the same optics, instrument electronics and in-flight calibration components for the whole wavelength range of 7- 14μm (TIS) and 7-40μm (TIR). MERTIS successfully completed its planned tests of the Near-Earth Commissioning Phase (NECP) between 13 and 14 November, collecting thousands of measurements of its internal calibration bodies and deep space. The data collected during NECP, are being used to verify the operational performances of onboard sub-modules, in particular the spectrometer and radiometer sensor sensitivity. A preliminary look at calibrated data shows a performance comparable with ground-based measurements and no appreciable performance loss or misalignment. The next important dates for MERTIS are the Earth/Moon flyby on 6 April 2020 and the first Venus flyby on 12 October 2020. Both those encounters will be important both for further instrument calibration refinement and for possible unprecedented measurement in the thermal infrared of the Moon and Venus.
Published: 2021

11. Near Surface Properties of Martian Regolith Derived From InSight HP3-RAD Temperature Observations During Phobos Transits

Author: Christian Krause, Justin N. Maki, François Forget, Ehouarn Millour, Sue Smrekar, Matthew A. Siegler, Nils Mueller, Sylvain Piqueux, William B. Banerdt, T. Spohn, Troy L. Hudson, Ralph D. Lorenz, Nicholas Attree, Mark T. Lemmon, Matthias Grott, Matthew P. Golombek, A. Hagermann, Jörg Knollenberg, DLR Institute of Planetary Research, German Aerospace Center (DLR), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Space Science Institute [Boulder] (SSI), Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), International Space Science Institute [Bern] (ISSI), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Luleå University of Technology (LUT), University of Stirling, Huffington Department of Earth Sciences [SMU Dallas], and Southern Methodist University (SMU)
Subjects: Martian, Materials science, phobos transit, 010504 meteorology & atmospheric sciences, Diurnal temperature variation, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Thermal conduction, thermal inertia, 01 natural sciences, Regolith, Computational physics, Geophysics, Thermal conductivity, 13. Climate action, Diurnal cycle, Martian surface, 0103 physical sciences, Thermal, General Earth and Planetary Sciences, thermal conductivity, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: International audience; AbstractWe use the Martian surface temperature response to Phobos transits observed next to the InSight lander in Elysium Planitia to constrain the thermal properties of the uppermost layer of regolith. Modeled transit lightcurves validated by solar panel current measurements are used to modify the boundary conditions of a 1D heat conduction model. We test several model parameter sets, varying the thickness and thermal conductivity of the top layer to explore the range of parameters that match the observed temperature response within its uncertainty both during the eclipse as well as the full diurnal cycle. The measurements indicate a thermal inertia (TI) of urn:x-wiley:00948276:media:grl62794:grl62794-math-0002 in the uppermost layer of 0.2–4 mm, significantly smaller than the TI of urn:x-wiley:00948276:media:grl62794:grl62794-math-0003 derived from the diurnal temperature curve. This could be explained by larger particles, higher density, or some or slightly higher amount of cementation in the lower layers.Plain Language SummaryThe Mars moon Phobos passed in front of the Sun from the perspective of the InSight lander on several occasions. The Mars surface temperatures measured by the lander became slightly colder during these transits due to the lower amount of sunlight the surface received at this time. The transits only last 20–35 s and therefore only the very top layer, about 0.3–0.8 mm, of the ground has time to cool significantly. The top layer cools and heats up faster than we expected based on the temperature changes of the day-night cycle, which affects about 4 cm of the ground. Based on this observation we conclude that the material in the top mm of the ground is different from that below. A possible explanation would be an increase of density with depth, a larger fraction of smaller particles such as dust at the top, or a layer where particles are slightly cemented together beginning at 0.2–4 mm below the surface.
Published: 2021
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12. The CoPhyLab comet-simulation chamber

Author: Patrick Tiefenbacher, T. Gilke, David Haack, Holger Sierks, H. L. Capelo, Erika Kaufmann, Carsten Güttler, Dorothea Bischoff, Anthony Lethuillier, Bastian Gundlach, M. Schweighart, Jörg Knollenberg, Katharina A. Otto, Wolfgang Macher, Christopher Kreuzig, N. Hänni, N. S. Molinski, Antoine Pommerol, Ekkehard Kührt, Jürgen Blum, Clement Feller, and G. Kargl
Subjects: International research, Scientific instrument, Cooling technology, Planet formation, Solar System, Mass spectrometry, Sample (material), 520 Astronomy, Comet, CoPhyLab, Mechanics, Solar illumination, Radiation, 620 Engineering, Mechanical instruments, Sample handling, Water cooling, Comets, Instrumentation, Solar system
Abstract: The Comet Physics Laboratory (CoPhyLab) is an international research program to study the physical properties of cometary analog materials under simulated space conditions. The project is dedicated to studying, with the help of multiple instruments and the different expertise and background from the different partners, the physics of comets, including the processes inside cometary nuclei, the activity leading to the ejection of dust and gas, and the sub-surface and surface evolution of cometary nuclei when exposed to solar illumination. CoPhyLab will provide essential information on the formation and evolution of comets and insights into the origins of primitive Solar System bodies. To this end, we constructed a new laboratory that hosts several small-scale experiments and a large-scale comet-simulation chamber (L-Chamber). This chamber has been designed and constructed to host ice��dust samples with a diameter of up to 250 mm and a variable height between 100 and 300 mm. The cometary-analog samples will be kept at temperatures below 120 K and pressures around 10��6 mbar to ensure cometary-like conditions. In total, 14 different scientific instruments are attached to the L-Chamber to study the temporal evolution of the physical properties of the sample under different insolation conditions. Due to the implementation of a scale inside the L-Chamber that can measure weight changes of the samples with high precision, the cooling system is mechanically decoupled from the sample holder and cooling of the samples occurs by radiation only. The constructed chamber allows us to conduct uninterrupted experiments at low temperatures and pressures up to several weeks.
Published: 2021
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13. The Mercury Radiometer and Thermal Infrared imaging Spectrometer (mertis) onboard Bepi Colombo: 2020 Moon flybys data results

Author: Alessandro Maturilli, Rainer Berlin, Jörg Knollenberg, Mario D'Amore, Thomas Säuberlich, Jörn Helbert, Gisbert Peter, and Harald Hiesinger
Subjects: Colombo, flybys, Thermal infrared, Radiometer, Imaging spectrometer, imaging, chemistry.chemical_element, Mercury, data results, Spectrometer, Mercury (element), chemistry, Thermal, Bepi, Environmental science, Infrared, Moon, Remote sensing
Abstract: Introduction: The MErcury Radiometer and Thermal Infrared Spectrometer (MERTIS) is an instrument to study the mineralogy and temperature distribution of Mercury’s surface in unprecedented detail [1]. During the nominal mission, MERTIS will map the whole surface at 500 m scale, combining a push-broom IR grating spectrometer (TIS) with a radiometer (TIR) sharing the same optics, instrument electronics, and in-flight calibration components for the whole wavelength range of 7-14µm (TIS) and 7-40µm (TIR) [1]. MERTIS successfully completed its planned tests of the Near-Earth Commissioning Phase (NECP) in November 2018 and several checkouts, collecting thousands of measurements of its internal calibration bodies and deep space. Those data show a performance comparable with ground-based measurements. Scientific data will arrive well before the 2025 arrival at Mercury. MERTIS observed the Moon on in April 2020 producing ~12k TIS observation with ~3k measurements of the Moon at various angles. Even if the Moon is 7000 farther away and half maximum temperature than Mercury during nominal operation, the signal is clearly visible and shows the excellent MERTIS TIS sensor. MERTIS archival data are stored in Planetary Data System v4 format (PDS4) [2] format, that actually describe 2 physical formats for each MERTIS channel. Each channel will be stored in Flexible Image Transport System (FITS) [3] and in pure ASCII. The Mission and the Instrument: BepiColombo [2] is a dual spacecraft mission to Mercury that has been launched in October 2018 and is jointly carried out by the European Space Agency (ESA) and the Japanese Aerospace Exploration Agency (JAXA). The spacecraft comprises two separate orbiters: the Mercury Planetary Orbiter (MPO), focused on observations of the surface and internal composition, and the Mercury Magnetospheric Orbiter (MMO), which will study the particle science in the extreme thermal environment. In addition to a suite of instruments complementary to the NASA MESSENGER mission, BepiColombo will be able to observe both the northern and southern hemispheres at high spatial resolution. BepiColombo uses an innovative solar electric propulsion system and its trajectory toward Mercury is a combination of low-thrust arcs and flybys at Earth, Venus, and Mercury. This will allow us to reach Mercury with low relative velocity. The spacecraft was successfully launched on the 20th of October 2018, 01:45 UTC, from the ESA Guiana Space Centre using an Ariane 5 rocket and will reach its mappings orbit at Mercury in 2026. The MERTIS instrument was proposed in 2003 as payload of the Mercury Planetary Orbiter spacecraft of the ESA-JAXA BepiColombo mission and the final Flight Model (FM) was delivered in 2013. MERTIS is an innovative and compact spectrometer, that combines a push-broom IR grating spectrometer (TIS) with a radiometer (TIR) with only 3kg of mass and an average 10 W power consumption [1,4]. TIS operates between 7 and 14 μm and will record the day-side emissivity spectra from Mercury, whereas TIR is going to measure the surface temperature at the day- and night side in the spectral range from 7-40 μm corresponding to temperatures from 80- 700 K. TIR is implemented by an in-plane separation arrangement, while TIS is an imaging spectrometer with an uncooled micro-bolometer array. The optical design of MERTIS combines a three-mirror anastigmatic lens (TMA) with a modified Offner grating spectrometer. A pointing device allows viewing the planet (through the planet-baffle), deep space (through the space-baffle), and two internal black bodies at 300 K and 700 K temperature, respectively. MERTIS was developed at DLR in collaboration with the Westfälische Wilhel-Universität Münster and industry partners. The MPO operational plan foreseen a 2.3 hour low eccentricity orbit that allows MERTIS to achieve its 500 meters global mapping scientific goal. As confirmed by the NASA MESSENGER mission, due to the iron-poor nature of the surface the thermal infrared is the most useful wavelength range to study Mercury’s surface composition. Silicates as well as sulfides have characteristic spectral features in this range that MERTIS can map with high signal-to-noise ratio. The MERTIS spectrometer aims to capture data on the mineralogy whereas the radiometer surveys the thermal inertia of the planet. Flyby Results: MERTIS nominal nadir viewing port (Planet View) is obstructed by the MTM (Mercury Transfer Module) during the whole cruise to Mercury, while the Space View port is unobstructed and normally used for calibration purpose. We trick MERTIS nominal observation cycle (Internal reference Blackbodies, Space, multiple Space) to acquire only from the Space port. We collect ~12k TIS observation, with more than 3000 spectra from the Moon. The acquisition campaign was split in 8 “observation”, that describe different modes of the instrument. During the Flyby the only TIS sensor binning was change to test different acquisition modes. A typical observation crossing the Moon is in Fig.1. The spectra radiance values are sharply decaying towards the Moon edges. The Moon is a much colder target than Mercury (around 400K max vs. 700K) and is it farther than the planned target distance during the nominal mission at Mercury (700.000 km vs ~1000 km ). The signal from the Moon is nevertheless clearly discernible from the background. The PI Team at DLR and Münster University is currently testing the calibration procedures and geometrical registration and on the verge to deliver the first calibrated data acquired in space to the CoI team. The final data format is still to be defined, but the data container will be the same as in the RAW level data [6] available on ESA PSA website[7]. References: [1] Hiesinger, H. and Helbert, J., Planet. Space Sci. 58, (2010). [2] NASA Planetary Data System, pds.nasa.gov [3] FITS Support Office, fits.gsfc.nasa.gov [4] Instrument User Manual (FM), MER-DLR-MA-001 (2017). [5] Python PDS4 Tools, SBN sbndev.astro.umd.edu/wiki [6] D’Amore et al, LPSC 2020, 2020LPI....51.1438D [7] European Space Agency's Planetary Science Archive (PSA) archives.esac.esa.int/psa Fig.1 left: Calibrated spectra radiance in W/(m² µm sr). right: Same spectra as in the first panel, as produced from TIS sensor (y is spatial direction , x is reversed spectral direction).
Published: 2020
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14. CoPhyLab: recent and future experiments - an overview

Author: Ekkehard Kührt, Jörg Knollenberg, Nicolas Thomas, Christopher Kreuzig, Katharina A. Otto, Clement Feller, Jürgen Blum, Axel Hagermann, Xiaojing Zhang, Maria Schweighart, Bastian Gundlach, Holger Sierks, David Haack, Noah Molinski, Günter Kargl, Dorothea Bischoff, Erika Kaufmann, Antoine Pommerol, Carsten Güttler, and Anthony Lethuillier
Abstract: CoPhyLabLaboratory experiments are of major importance to understand the activity of comets and to support future space missions. However, past comet simulation experiments were performed under the assumption that comets are mainly composed of water ice with only a limited amount of dust. In the past years, however, the Rosetta mission has shown that cometary nuclei consist primarily of dust and less volatile materials are present than previously thought. Hence, it is high time to set up a new series of laboratory experiments with the aim to investigate the physics of realistic cometary analogue materials. This task is currently addressed by the CoPhyLab (Comet Physics Laboratory) which is a joint project among different partner institutions. This laboratory aims at studying the physics of cometary analogue materials. This task is approached by firstinvestigating isolated physical properties in so-called small experiments (S experiments). In a next step, the experiment’s complexity is increased step-by-step by either adding further components to the sample, or by studying several physical properties under different conditions (large experiments, which will be performed in the L chamber). S1: the tensile strength of organic materialsThe knowledge of the tensile strength of the cometary surface is of key importance to better understand the activity of comets. The tensile strength determines the strain required to detach material from the surface. As organic materials are ubiquitous in space, they could have played an important role during the planet formation process and are most likely incorporated into cometary nuclei. This S experiment campaign provides new measurements on the tensile strength of various granular organic materials. These materials are investigated by the Brazilian Disc Test and the measured values are normalised to a grain size of one micrometer and a volume filling factor of 0.5 for better comparability. The experiments show that the tensile strength of organic materials ranges over four orders of magnitude. Graphite and paraffin have much higher tensile strengths values compared to silica, whereas the tensile strength of coals is very low. This work demonstrates that organic materials are not generally stickier than silicates, or water ice. S2: gas permeability of analogue materials The cometary nucleus is made of water ice, organics and silicateous dust and the ice is trapped inside the matrix of non-volatiles. Hence, the evolving gas has to stream away from its originating region inside the surface layers towards the surface. This work package has the aim to investigate the gas transport mechanisms through porous cometary analogue materials. Therefore, gas flow measurements are performed to investigate the permeability of several materials, which are chosen to mimic cometary surface properties. With these measurements, the gas permeability and the Knudsen diffusion coefficient of the sample materials are obtained. These simulants are tested with respect to different filling heights, packing properties and grain shapes. The gas flow experiments show that the grain size distribution and the packing density of the samples are primarily influencing the permeability of the sample. S3: thermal conductivity of analogue materialsMeasurements of the thermal properties of analogue materials are essential in interpreting remote sensing data and the findings of in-situ instruments. The thermal properties of the subsurface layers determine the surface temperature of asteroids and comets. The temperature stratification inside planetary object is a key parameter to understand the processing of their interior. This experiment campaign is dedicated to measure the thermal properties of analogue materials. In preparation for these measurements we have set up a small vacuum chamber equipped with an infrared camera and temperature sensors. The samples are illuminated for a short duration by a laser. We then compare the measured temperature profiles with the predictions of a thermophysical model to determine the thermal conductivity of the samples. S4: ejection of materialWhen comets approach the Sun, the sublimation pressure will be reached inside the material. If the tensile strength is exceeded by the evolving pressure, the particles can be ejected from the cometary surface and are accelerated. However, the details of the dust dynamics close to the surface are not understood in detail. The idea of this S experiment campaign is to develop an experimental routine to track ejected particles from a sample composed of granular water ice. Therefore, we recorded the power of the illumination, the temperature of the sample and measured the particle trajectories with an high speed camera. Furthermore, the experiments are also simulated by a thermophysical model. Our experiments show that samples composed of pure granular water ice can eject water-ice particles by the pressure build up of water vapour in their interior. Compressed samples posses an higher activity level (ejection events per second) compared to uncompressed samples. The ejected particles have a non-zero initial velocity which is most probably caused by a very fast acceleration of the particles before the first data point is recorded by the camera. The L chamberThe core of this project is the realisation of a comet simulation chamber which will be capable to utilise multiple instruments to monitor and measure the sample properties before, during and after the experiment campaigns. This chamber will be used to perform long duration experiments at low temperatures and low pressures. At this stage (end of June, 2020), the chamber is already installed in place and is vacuum tight, the cooling shield is assembled and the sample carrier cart as well as the self-made glove box are ready to use. The next steps comprise the integration of the cooling shield and the main cooling system. We foresee to run the first experiments in approximately six weeks from now. During the EPSC conference we will provide a technical overview of the chamber and we will present the first experiments performed in the L chamber. AcknowledgementsThis work was carried out in the framework of the CoPhyLab project funded by the D-A-CH programme (GU 1620/3-1 and BL 298/26-1 / SNF 200021E 177964 / FWF I 3730-N36). DB and JB thank the Deutsches Zentrum f\"ur Luft- und Raumfahrt for support under grant 50WM1846.
Published: 2020
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15. Mars Regolith Properties as Constrained from HP3 Mole Operations and Thermal Measurements

Author: Nils Müller, Torben Wippermann, Susanne Smrekar, K. Hurst, Robert G. Deen, Matthias Grott, Roy Lichtenheldt, Jörg Knollenberg, Cinzia Fantinati, Eloise Marteau, Ann Louise Thomas, S. Piqueux, Matthew P. Golombek, Troy L. Hudson, Tilman Spohn, and Christian Krause
Subjects: Raumfahrt-Systemdynamik, Institut für Planetenforschung, Mars Exploration Program, Regolith, Institut für Systemdynamik und Regelungstechnik, Nutzerzentrum für Weltraumexperimente (MUSC), Astrobiology, Planetenphysik, Institut für Raumfahrtsysteme, Thermal, Mole, Land und Explorationstechnologie, InSight HP3 Mars Regolith, Geology
Abstract: The Heat Flow and Physical Properties Package HP3 onboard the Nasa InSight mission has been on the surface of Mars for more than one Earth year. The instrument's primary goal is to measure Mars' surface heat flow through measuring the geothermal gradient and the thermal condunctivity at depths between 3 and 5m. To get to depth, the package includes a penetrator nicknamed the "Mole" equipped with sensors to precisely measure the thermal conductivity. The Mole tows a tether with printed temperature sensors; a device to measure the length of the tether towed and a tiltmeter will help to track the path of the Mole and the tether. Progress of the Mole has been stymied by difficulties of digging into the regolith. The Mole functions as a mechanical diode with an internal hammer mechanism that drives it forward. Recoil is balanced mostly by internal masses but a remaining 3 to 5N has to be absorbed by hull friction. The Mole was designed to work in cohesionless sand but at the InSight landing a cohesive duricrust of at least 7cm thickness but possibly 20cm thick was found. Upon initial penetration to 35cm depth, the Mole punched a hole about 6cm wide and 7cm deep into the duricrust, leaving more than a fourth of its length without hull friction. It is widely agreed that the lack of friction is the reason for the failure to penetrate further. The HP3 team has since used the robotic arm with its scoop to pin the Mole to the wall of the hole and helped it penetrate further to almost 40cm. The initial penetration rate of the Mole has been used to estimate a penetration resistance of 300kPa. Attempts to crush the duricrust a few cm away from the pit have been unsuccessful from which a lower bound to the compressive strength of 350kPa is estimated. Analysis of the slope of the steep walls of the hole gave a lower bound to cohesion of 10kPa. As for thermal properties, a measurement of the thermal conductivity of the regolith with the Mole thermal sensors resulted in 0.045 Wm-1K-1. The value is considerably uncertain because part of the Mole having contact to air. The HP³ radiometer has been monitoring the surface temperature next to the lander and a thermal model fitted to the data give a regolith thermal inertia of 189 ± 10 J m-2 K-1 s-1/2. With best estimates of heat capacity and density, this corresponds to a thermal conductivity of 0.045 Wm-1K-1, consistent with the above measurement using the Mole. The data can be fitted well with a homogeneous soil model, but observations of Phobos eclipses in March 2019 indicate that there possibly is a thin top layer of lower thermal conductivity. A model with a top 5 mm layer of 0.02 Wm-1K-1 above a half-space of 0.05 Wm-1K-1 matches the amplitudes of both the diurnal and eclipse temperature curves. Another set of eclipses will occur in April 2020.
Published: 2020
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16. The MASCOT lander aboard Hayabusa2: The in-situ exploration of NEA (162173) Ryugu

Author: Matthias Grott, Oliver Küchemann, Eugen Ksenik, Cinzia Fantinati, Celine Cenac-Morthe, U. Auster, Markus Schlotterer, Kaname Sasaki, Volodymyr Baturkin, Michael Maibaum, Christian Krause, Michael Lange, Barbara Cozzoni, Nortbert Toth, Jean-Pierre Bibring, Jörg Knollenberg, J. T. Grundmann, Takanao Saiki, Tetsuo Yoshimitsu, Christian Grimm, Maximilian Hamm, K. Otto, Josef Reill, Clement Dudal, Jens Biele, Kagan Kayal, Yuichi Tsuda, Cedric Pilorget, Tra-Mi Ho, David Hercik, Laurence Lorda, Caroline Lange, Stephan Ulamec, Tatsuaki Okada, Nicole Schmitz, Yuya Mimasu, Aurelie Moussi, Nawarat Termtanasombat, Federico Cordero, Friederike Wolff, K.H. Glaßmeier, Ralf Jaumann, Christan Ziach, and Stefan Schröder
Subjects: First contact, 010504 meteorology & atmospheric sciences, Spacecraft, business.industry, Payload, Cruise, Astronomy and Astrophysics, Terrain, 01 natural sciences, Asteroid In-situ surface science Lander Operations Camera IR Spectrometer Magnetometer Radiometer, Astrobiology, Mascot, Space and Planetary Science, Asteroid, 0103 physical sciences, business, 010303 astronomy & astrophysics, Geology, Communication Contact, 0105 earth and related environmental sciences
Abstract: After 3.5 years of cruise, and about 3 months in the vicinity of its target, the MASCOT lander was deployed successfully on October 3, 2018 by the Hayabusa2 spacecraft onto the C-type near-Earth asteroid (162173) Ryugu. After a free-fall of 5 min 51 s from an altitude of 41 m MASCOT experienced its first contact with the asteroid hitting a big boulder. The lander bounced for ~11 min 3 s before it came to rest. MASCOT was able to perform science measurements with its payload suite at 3 different locations on the surface of Ryugu. It investigated the fine-scale structure, multispectral reflectance, thermal characteristics and magnetic properties. The surface consists of very rugged terrain littered with large surface boulders. The in-situ measurements confirmed the absence of fine particles and dust as already implied by the remote sensing instruments aboard the Hayabusa2 spacecraft. After about 17 h of operations, the MASCOT mission terminated with the last communication contact as its primary batteries depleted. This paper summarizes the MASCOT mission covering its four years of in-flight operations, its preparation for the descent, landing and in-situ investigation on the asteroid Ryugu until the end of its operation.
Published: 2021
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17. Long-term monitoring of comet 67P/Churyumov–Gerasimenko’s jets with OSIRIS onboard Rosetta

Author: Holger Sierks, Ekkehard Kührt, Philippe Lamy, L. M. Lara, Marco Fulle, M. De Cecco, Monica Lazzarin, H. U. Keller, A. Gicquel, M. I. Schmitt, Dennis Bodewits, Xian Shi, Jessica Agarwal, J. J. López-Moreno, Imre Toth, M. F. A'Hearn, Stefano Mottola, Olivier Groussin, Sonia Fornasier, R. Rodrigo, J. L. Bertaux, Frank Scholten, Cesare Barbieri, D. Prasanna, Jörg Knollenberg, Stefano Debei, Jakob Deller, Wing-Huen Ip, Stubbe F. Hviid, Carsten Güttler, Björn Davidsson, Cecilia Tubiana, Laurent Jorda, Nilda Oklay, Ivano Bertini, Michael Küppers, Detlef Koschny, Nicolas Thomas, G. Cremonese, Francesco Marzari, J.-B. Vincent, V. Da Deppo, Mohamed Ramy El-Maarry, Marc Hofmann, Maurizio Pajola, Hans Rickman, J.-R. Kramm, P. J. Gutierrez, M. A. Barucci, Giampiero Naletto, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Università degli Studi di Padova = University of Padua (Unipd), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Department of Physics and Astronomy [Uppsala], Uppsala University, Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Department of Industrial Engineering [Padova], University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Operations Department (ESAC), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Department of Information Engineering [Padova] (DEI), NASA Ames Research Center (ARC), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), Center for Space and Habitability (CSH), University of Bern, Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Max-Planck-Institut für Sonnensystemforschung (MPS), Universita degli Studi di Padova, European Space Agency (ESA), Consiglio Nazionale delle Ricerche [Roma] (CNR), California Institute of Technology (CALTECH)-NASA, European Space Agency (ESA)-European Space Agency (ESA), Universität Bern [Bern], Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), ITA, USA, GBR, FRA, and DEU
Subjects: 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, Epoch (astronomy), Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Equinox, 01 natural sciences, Latitude, 0103 physical sciences, comets, Comets: individual: 67P/Churyumov, Gerasimenko, 010303 astronomy & astrophysics, Southern Hemisphere, 0105 earth and related environmental sciences, [PHYS]Physics [physics], Physics, Jet (fluid), biology, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 520 Astronomy, Northern Hemisphere, Astronomy, Astronomy and Astrophysics, 620 Engineering, biology.organism_classification, 13. Climate action, Space and Planetary Science, Osiris, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; We used the OSIRIS camera system onboard the Rosetta spacecraft to monitor jet activity of comet 67P/Churyumov-Gerasimenko. With a monthly cadence, we covered an epoch from December 2014 to October 2015, thereby including the first equinox and the perihelion passage. Jet features were measured in individual images, which were used to perform a statistical inversion. The study provides maps for the locations of likeliest sources of jet activity on the comet’s surface as a function of time. The sources follow the sub-solar latitude, show clustering and a broadening of the activity band with time in the Northern hemisphere. On the Southern hemisphere they are not clustered but show a broader spread over all longitudes which is either related to the north-south dichotomy of the comet’s topography or due to a higher insolation during southern summer.
Published: 2017
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18. Long-term survival of surface water ice on comet 67P

Author: Alice Lucchetti, M. De Cecco, R. Rodrigo, Michael Küppers, Laurent Jorda, Ivano Bertini, Nilda Oklay, W-H. Ip, Detlef Koschny, Marc Hofmann, J. L. Bertaux, Frank Scholten, Nicolas Thomas, J.-R. Kramm, V. Da Deppo, Clement Feller, P. J. Gutierrez, Dennis Bodewits, Sonia Fornasier, Carsten Güttler, I. Hall, Maurizio Pajola, Nafiseh Masoumzadeh, Francesco Marzari, Marco Fulle, A. Gicquel, M. A. Barucci, Jörg Knollenberg, Holger Sierks, Cesare Barbieri, Monica Lazzarin, Jakob Deller, Zhong-Yi Lin, David Kappel, Olivier Groussin, J. J. Lopez Moreno, Jean-Baptiste Vincent, Horst Uwe Keller, Michael F. A'Hearn, Luisa Lara, Giampiero Naletto, Pedro Hasselmann, Björn Davidsson, Cecilia Tubiana, Philippe Lamy, Antoine Pommerol, Stubbe F. Hviid, Hans Rickman, Frank Preusker, Xian Shi, Stefano Mottola, Gábor L. Kovács, Gabriele Cremonese, Ekkehard Kührt, J. D. P. Deshapriya, Stefano Debei, DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), NASA Ames Research Center (ARC), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Dipartimento di Fisica e Astronomia 'Galileo Galilei', Università degli Studi di Padova = University of Padua (Unipd), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Department of Physics and Astronomy [Uppsala], Uppsala University, Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Department of Industrial Engineering [Padova], University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Operations Department (ESAC), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Department of Information Engineering [Padova] (DEI), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Max-Planck-Institut für Sonnensystemforschung (MPS), Universita degli Studi di Padova, Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), European Space Agency (ESA), Consiglio Nazionale delle Ricerche [Roma] (CNR), European Space Agency (ESA)-European Space Agency (ESA), Universität Bern [Bern], and California Institute of Technology (CALTECH)-NASA
Subjects: Asteroiden und Kometen, 010504 meteorology & atmospheric sciences, Infrared, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Techniques: image processing, Narrow angle, Astrophysics, 01 natural sciences, Methods: data analysis, 0103 physical sciences, Long term survival, Techniques: imaging spectroscopy, Variation (astronomy), 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Comets: individual: 67P/Churyumov-Gerasimenko, Physics, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 520 Astronomy, Leitungsbereich PF, Planetengeodäsie, Astronomy and Astrophysics, 620 Engineering, 13. Climate action, Space and Planetary Science, Water ice, Surface water
Abstract: Numerous water-ice-rich deposits surviving more than several months on comet 67P/Churyumov-Gerasimenko were observed during the Rosetta mission. We announce the first-time detection of water-ice features surviving up to 2 yr since their first observation via OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System) NAC (narrow angle camera). Their existence on the nucleus of comet 67P at the arrival of the Rosetta spacecraft suggests that they were exposed to the surface during the comet's previous orbit. We investigated the temporal variation of large water-ice patches to understand the long-term sustainability of water ice on cometary nuclei on time-scales of months and years. Large clusters are stable over typical periods of 0.5 yr and reduce their size significantly around the comet's perihelion passage, while small exposures disappear. We characterized the temporal variation of their multispectral signatures. In large clusters, dust jets were detected, whereas in large isolated ones no associated activity was detected. Our thermal analysis shows that the long-term sustainability of water-ice-rich features can be explained by the scarce energy input available at their locations over the first half year. However, the situation reverses for the period lasting several months around perihelion passage. Our two end-member mixing analysis estimates a pure water-ice equivalent thickness up to 15 cm within one isolated patch, and up to 2 m for the one still observable through the end of the mission. Our spectral modelling estimates up to 48 per cent water-ice content for one of the large isolated feature, and up to 25 per cent water ice on the large boulders located within clusters.
Published: 2017
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19. Modelling of the outburst on 2015 July 29 observed with OSIRIS cameras in the Southern hemisphere of comet 67P/Churyumov–Gerasimenko

Author: N. Oklay, Holger Sierks, Stefano Mottola, F. Preusker, Ivano Bertini, J.-R. Kramm, Géza Kovács, Jessica Agarwal, Michael Küppers, Nicolas Fougere, Giampiero Naletto, Matteo Massironi, F. Moreno, Mohamed Ramy El-Maarry, Hans Rickman, Sebastien Besse, Stephen C. Lowry, Stubbe F. Hviid, Monica Lazzarin, Xian Shi, L. M. Lara, A. Gicquel, Marco Fulle, S. Höfner, M. A. Barucci, J. B. Vincent, Jörg Knollenberg, M. F. A'Hearn, V. Da Deppo, Olivier Groussin, P. Gutiérrez-Marquez, Rafael Rodrigo, Francesco Marzari, Nafiseh Masoumzadeh, X. Hu, M. De Cecco, M. Rose, Ekkehard Kührt, Stefano Debei, Imre Toth, Cesare Barbieri, Björn Davidsson, Sonia Fornasier, Cecilia Tubiana, Jakob Deller, Gabriele Cremonese, Maurizio Pajola, Zhong-Yi Lin, F. Scholten, Wing-Huen Ip, Laurent Jorda, Detlef Koschny, Nicolas Thomas, P. J. Gutierrez, Marc Hofmann, Steve Boudreault, J. J. Lopez Moreno, Philippe Lamy, Dennis Bodewits, E. Frattin, Carsten Güttler, H. U. Keller, J. L. Bertaux, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, PI-DSMC software package, DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Department of Climate and Space Sciences and Engineering (CLaSP), University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Università degli Studi di Padova = University of Padua (Unipd), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), International Space Science Institute [Bern] (ISSI), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Physics and Astronomy [Uppsala], Uppsala University, Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Research and Scientific Support Department, ESTEC (RSSD), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Department of Industrial Engineering [Padova], University of Trento [Trento], Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Department of Mechatronics, Optics and Mechanical Engineering Informatics (MOMEI), Budapest University of Technology and Economics [Budapest] (BME), European Space Astronomy Centre (ESAC), School of Physical Sciences [Canterbury], University of Kent [Canterbury], Department of Information Engineering [Padova] (DEI), NASA Ames Research Center (ARC), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), ITA, USA, GBR, FRA, DEU, Max-Planck-Institut für Sonnensystemforschung (MPS), Universita degli Studi di Padova, Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), European Space Agency (ESA), European Space Agency (ESA)-European Space Agency (ESA), Consiglio Nazionale delle Ricerche [Roma] (CNR), Universität Bern [Bern], and California Institute of Technology (CALTECH)-NASA
Subjects: 010504 meteorology & atmospheric sciences, Infrared, Comet, Data analysis, Comets: individual: 67P/Churyumov-Gerasimenko, Methods: data analysis, Methods: numerical, Methods: observational, 67P/Churyumov, Coma (optics), Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, modelling, comet, Rosetta, 0103 physical sciences, Comets, High spatial resolution, Astrophysics::Solar and Stellar Astrophysics, OSIRIS, 010303 astronomy & astrophysics, Southern Hemisphere, Observations, Astrophysics::Galaxy Astrophysics, Gerasimenko, 0105 earth and related environmental sciences, Numerical, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], [PHYS]Physics [physics], Physics, 67P, biology, 520 Astronomy, outburt, Astronomy, Astronomy and Astrophysics, Radius, 620 Engineering, biology.organism_classification, Outgassing, 13. Climate action, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Osiris, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; Images of the nucleus and the coma (gas and dust) of comet 67P/Churyumov– Gerasimenko have been acquired by the OSIRIS (Optical, Spectroscopic and Infrared Remote Imaging System) cameras since 2014 March using both the wide-angle camera and the narrow-angle camera (NAC). We use images from the NAC camera to study a bright outburst observed in the Southern hemisphere on 2015 July 29. The high spatial resolution of the NAC is needed to localize the source point of the outburst on the surface of the nucleus. The heliocentric distance is 1.25 au and the spacecraft–comet distance is 186 km. Aiming to better understand the physics that led to the outgassing, we used the Direct Simulation Monte Carlo method to study the gas flow close to the nucleus and the dust trajectories. The goal is to understand the mechanisms producing the outburst. We reproduce the opening angle of the outburst in the model and constrain the outgassing ratio between the outburst source and the local region. The outburst is in fact a combination of both gas and dust, in which the active surface is approximately 10 times more active than the average rate found in the surrounding areas. We need a number of dust particles 7.83 × 1011 to 6.90 × 1015 (radius 1.97–185 μm), which correspond to a mass of dust (220–21) × 103 kg.
Published: 2017
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20. Three-dimensional illumination and thermal model of the Abydos region on comet 67P/Churyumov-Gerasimenko

Author: Barbara Cozzoni, Jörg Knollenberg, Patrick Tiefenbacher, Felix Finke, Claire Capanna, Wolfgang Macher, Valentina Lommatsch, Tilman Spohn, Norbert I. Kömle, Laurent Jorda, Ivanka Pelivan, and Günter Kargl
Subjects: Physics, 010504 meteorology & atmospheric sciences, Space and Planetary Science, 0103 physical sciences, Comet, Radiative transfer, Astronomy, Astronomy and Astrophysics, Thermal model, 010303 astronomy & astrophysics, 01 natural sciences, 0105 earth and related environmental sciences
Published: 2017
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21. Low thermal conductivity boulder with high porosity identified on C-type asteroid (162173) Ryugu

Author: Maximilian Hamm, Nicole Schmitz, Shogo Tachibana, Matthias Grott, Alessandro Maturilli, Ivanka Pelivan, Kazunori Ogawa, Takehiko Arai, Frank Trauthan, Patrick Michel, Marco Delbo, Axel Hagermann, Jörn Helbert, Satoshi Tanaka, Nils Müller, Wladimir Neumann, Naoya Sakatani, Tra-Mi Ho, Stefano Mottola, K-D Matz, Jörg Knollenberg, Alexander Koncz, Stefan Schröder, Jens Biele, Christian Krause, Ralf Jaumann, Jean-Baptiste Vincent, Line Drube, Katharina A. Otto, Hajime Yano, Aurelie Moussi-Soffys, Markus Schlotterer, Hiroki Senshu, C. Pilorget, Martin Knapmeyer, Tatsuaki Okada, Ekkehard Kührt, German Aerospace Center (DLR), DLR Institute of Planetary Research, Institut de Science des Matériaux de Mulhouse (IS2M), Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Deutsches Zentrum für Luft- und Raumfahrt (DLR), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), The Open University [Milton Keynes] (OU), Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), University of Potsdam, ANR-15-IDEX-0001,UCA JEDI,Idex UCA JEDI(2015), and Publica
Subjects: Solar System, 010504 meteorology & atmospheric sciences, Infrared, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Mineralogy, 01 natural sciences, Thermal conductivity, 0103 physical sciences, Ultimate tensile strength, Ryugu, Porosity, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Asteroiden, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Institut für Mathematik, Astronomy and Astrophysics, Regolith, Meteorite, Asteroid, [SDU]Sciences of the Universe [physics], ddc:520, Geology, Thermiscche Trägheit, Hayabusa2
Abstract: 著者人数: 37名 (所属. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS): 岡田, 達明; 坂谷, 尚哉; 田中, 智; 矢野, 創), Number of authors: 37 (Affiliation. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency(JAXA)(ISAS): Okada, Tatsuaki; Sakatani, Naoya; Tanaka, Satoshi; Yano, Hajime）, Accepted: 2019-06-04, 資料番号: SA1190164000
Published: 2019
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22. Correction to: The Thermal, Mechanical, Structural, and Dielectric Properties of Cometary Nuclei After Rosetta

Author: Ivanka Pelivan, Björn Davidsson, Olivier Groussin, Tilman Spohn, Jörg Knollenberg, Yuri V. Skorov, Federico Tosi, Yann Brouet, Gianrico Filacchione, Rosita Kokotanekova, C. Leyrat, Martin Knapmeyer, Bastian Gundlach, Ekkehard Kührt, Hans-Herbert Fischer, Nicholas Attree, David Marshall, Colin Snodgrass, Valérie Ciarletti, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Earth and Planetary Observation Centre (EPOC), University of Stirling, Physics Institute [Bern], University of Bern, PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), DLR Microgravity User Support Center (MUSC), Deutsches Zentrum für Luft- und Raumfahrt (DLR), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), School of Physical Sciences [Milton Keynes], Faculty of Science, Technology, Engineering and Mathematics [Milton Keynes], The Open University [Milton Keynes] (OU)-The Open University [Milton Keynes] (OU), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, European Southern Observatory (ESO), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Georg-August-University [Göttingen], German Research Centre for Geosciences - Helmholtz-Centre Potsdam (GFZ), Institute for Astronomy [Edinburgh] (IfA), University of Edinburgh, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), NASA-California Institute of Technology (CALTECH), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Georg-August-University = Georg-August-Universität Göttingen, Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Centre de recherches en physique de l'environnement terrestre et planétaire (CRPE), Centre National de la Recherche Scientifique (CNRS), Technische Universität Braunschweig [Braunschweig], The Open University [Milton Keynes] (OU), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Georg-August-Universität Göttingen, and German Aerospace Center (DLR)
Subjects: 010504 meteorology & atmospheric sciences, Computer science, Internet portal, Astronomy and Astrophysics, Creative commons, 01 natural sciences, Space and Planetary Science, Thermal mechanical, [SDU]Sciences of the Universe [physics], 0103 physical sciences, Calculus, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, License, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: Correction to: Space Sci. Rev. (2019) 215: 29 The article The Thermal, Mechanical, Structural, and Dielectric Properties of Cometary Nuclei After Rosetta, written by Groussin et al., was originally published electronically on the publisher’s internet portal (currently SpringerLink) on 2 May 2019 without open access. With the author(s)’ decision to opt for Open Choice the copyright of the article changed to © The Author(s) 2019 and the article is forthwith distributed under the terms of the Creative Commons Attribution 4.0 International License ( http://creativecommons.org/licenses/by/4.0/ ), which permits use, duplication, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license and indicate if changes were made.
Published: 2019
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23. Gas outflow and dust transport of comet 67P/Churyumov–Gerasimenko

Author: Francesco Marzari, Wing-Huen Ip, Laurent Jorda, J. Rainer Kramm, Hans Rickman, Gábor L. Kovács, Marc Hofmann, I. L. Lai, Philippe Lamy, Detlef Koschny, Jong-Shinn Wu, Mariolino De Cecco, Nilda Oklay, Ivano Bertini, Michael Küppers, Xian Shi, Nicolas Thomas, Stubbe F. Hviid, Jean-Loup Bertaux, Holger Sierks, C. Güttler, Olivier Groussin, Vania Da Deppo, Marco Fulle, Steven Boudreault, Pedro J. Gutiérrez, Giampiero Naletto, M. A. Barucci, Horst Uwe Keller, Michael F. A'Hearn, Jose J. Lopez Moreno, Jui Chi Lee, Ying Liao, Cesare Barbieri, Luisa Lara, Monica Lazzarin, Cheng Chin Su, Jean-Baptiste Vincent, Jakob Deller, Gabriele Cremonese, Ekkehard Kührt, Zhong-Yi Lin, Björn Davidsson, Cecilia Tubiana, Stefano Debei, Jessica Agarwal, Sonia Fornasier, Jörg Knollenberg, Rafael Rodrigo, Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Institute of Astronomy [Taiwan] (IANCU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Department of Mechanical Engineering [NCTU], National Chiao Tung University (NCTU), Department of Atmospheric Sciences [Taoyuan City], Physikalisches Institut [Bern], Universität Bern [Bern], Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Department of Physics and Astronomy [Uppsala], Uppsala University, Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Department of Industrial Engineering [Padova], University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), European Space Astronomy Centre (ESAC), Department of Information Engineering [Padova] (DEI), Universität Bern [Bern] (UNIBE), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Università degli Studi di Padova = University of Padua (Unipd), Agence Spatiale Européenne = European Space Agency (ESA), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), ITA, USA, GBR, FRA, and DEU
Subjects: individual: comet 67P/Churyumov-Gerasimenko [comets], 010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, Comet dust, Irregular shape, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, general [comets], methods: numerical, Astronomi, astrofysik och kosmologi, 0103 physical sciences, Comets: general, Comets: individual: comet 67P/Churyumov-Gerasimenko, Methods: numerical, Astronomy and Astrophysics, Space and Planetary Science, Astronomy, Astrophysics and Cosmology, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, Jet (fluid), [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Comet tail, 520 Astronomy, comets: general, Thermal cycle, Astronomy, numerical [methods], comets: individual: comet 67P/Churyumov-Gerasimenko, 620 Engineering, 13. Climate action, Outflow, Astrophysics::Earth and Planetary Astrophysics
Abstract: International audience; Because of the diurnal thermal cycle and the irregular shape of the nucleus, gas outflow of comet 67P/Churyumov–Gerasimenko could be highly anisotropic as indicated by the colliminated dust jet structures on the sunlit side. Based on the OSIRIS imaging observations of the outgassing effect, a simple model of surface sublimation can be constructed by taking into account the dependence on the solar insolation. With preliminary information on the time variability of the global gas production rate, a sequence of gas coma models can be generated at different epochs before and after perihelion. We also investigate different patterns of dust particle dynamics under the influences of nuclear rotation and gas drag. From these considerations, a consistent picture of the spatial distribution of dusty materials across the surface of comet 67P as it moves around the perihelion can be developed. It is found that because of the redeposition of the ejected dust from the Southern hemisphere to the Northern hemisphere during the southern summer season the Hapi region could gain up to 0.4 m while the Wosret region would lose up to 1.8 m of dust mantle per orbit.
Published: 2016
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24. Penetration and performance testing of the HP³ Mole for the InSight Mars mission

Author: Matthias Grott, Roy Lichtenheldt, Lars Witte, Olaf Krömer, Georgios Tsakyridis, Torben Wippermann, Troy L. Hudson, S. Hense, Jörg Knollenberg, T. Spohn, Mark Fittock, and Marco Scharringhausen
Subjects: Penetrator, 010504 meteorology & atmospheric sciences, German aerospace, Directional stability, Deep penetration, Exploration of Mars, 01 natural sciences, Penetration test, 0103 physical sciences, Aerospace engineering, 010303 astronomy & astrophysics, InSight, 0105 earth and related environmental sciences, business.industry, HP³, Astronomy and Astrophysics, Mars Exploration Program, Penetration (firestop), Mars exploration, Probe-soil-interaction, Mole, Space and Planetary Science, Environmental science, business, Heat flow
Abstract: During the development and the qualification of the Heat Flow Physical Properties Package (HP³) instrument (developed by the German Aerospace Center), which is part of the NASA Mars mission InSight, its self-propelling subsurface probe, the HP³ Mole was used in several penetration tests. Here, the performance of the Mole to reach the target depth, to avoid or overcome obstacles on its path, and its directional stability in the subsurface is elaborated. The different test beds and set ups are described and the results are presented. The deep penetration tests (DPT), with the purpose to reach the target depth, are the most important performance tests and therefore the results are investigated in more detail in section 2. Full functional tests (FFT), which showed the performance and degradation of the mechanism inside the Mole, are presented in section 3. Additional penetration and life cycle tests are described in section 4. The testing has demonstrated that the HP³ Mole meets all of its penetration requirements with margin.
Published: 2020
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25. Mapping Trojan asteroids in the thermal infrared with TROTIS

Author: Pierre Vernazza, Tatsuaki Okada, Ingo Walter, Matthias Grott, Gabriele Arnold, Ernesto Palomba, Andrew S. Rivkin, Mario D'Amore, Indhu Varatharajan, Thomas Säuberlich, Jörg Knollenberg, Alessandro Maturilli, Joern Helbert, Anko Boerner, and Gisbert Peter
Subjects: asteroids, Physics, Solar System, MERTIS, Radiometer, Spectrometer, Planetary science, Phase angle (astronomy), Asteroid, Trojan, Thermal, Trojans, thermal infrared, Remote sensing
Abstract: TROTIS (TROjan asteroid Thermal Infrared multi-Spectral imager) is a high spatial-resolution thermal imaging system optimized for targets in the outer solar system with heritage from the Miniaturized Asteroid thermal infrared Imager and Radiometer (MAIR) for the AIDA mission as well as Bepi-Colombo mission’s MErcury Radiometer and Thermal Infrared Spectrometer (MERTIS). TROTIS will provide unique science observations that will foster our understanding of Trojan asteroids. It will provide compositional information, thermal physical properties as well as help determine accurate shapes. In addition TROTIS can aid optical navigation, as it will be able to detect targets from any phase angle.
Published: 2018
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26. MASCOT – a Mobile Lander on-board Hayabusa2 Spacecraft – Status and Operational Concept for the Asteroid Ryugu

Author: Yuichi Tsuda, Takanao Saiki, Tetsuo Yoshimitsu, Josef Reill, Laurence Lorda, Jörg Knollenberg, Ul Auster, Stephan Ulamec, Nicole Schmitz, Kagan Kayal, Ralf Jaumann, D. Hercik, Aurelie Moussi, Vincent Hamm, Celine Cenac-Morthe, Jan Thimo Grundmann, Oliver Küchemann, Michael Maibaum, Jens Biele, Caroline Lange, Matthias Grott, Cinzia Fantinati, Clement Dudal, Karl-Heinz Glassmeier, Jean-Pierre Bibring, Schlotterer Markus, Hans-Herbert Fischer, Kaname Sasaki, Daniel May, Nawarat Termtanasombat, Barbara Cozzoni, Daniel Embacher, Christian Krause, David Granena, Tatsuaki Okada, Christian Ziach, and Tra-Mi Ho
Subjects: Asteroiden und Kometen, Engineering, 010504 meteorology & atmospheric sciences, Spacecraft, business.industry, MASCOT, Systementwicklung und Projektbüro, 01 natural sciences, Nutzerzentrum für Weltraumexperimente (MUSC), Mechatronische Systeme, Planetengeologie, On board, Mascot, Planetenphysik, Asteroid, 0103 physical sciences, Asteroid Ryugu, Navigations- und Regelungssysteme, Aerospace engineering, business, 010303 astronomy & astrophysics, Hayabusa2, 0105 earth and related environmental sciences
Abstract: MASCOT (‘Mobile Asteroid Surface Scout’) is a 10 kg mobile surface science package on board JAXA’s Hayabusa2 sample return mission, currently on its way to the near-Earth asteroid (162173) Ryugu. The mission was launched in December 2014 from Tanegashima Space Center, Japan. The Hayabusa2 spacecraft will reach the target asteroid in summer 2018. Hayabusa2 will return its samples to Earth in December 2020. After arrival at the target asteroid ‘Ryugu’ a detailed mapping phase will be performed and the landing site of MASCOT will be selected. The deployment of MASCOT to the asteroids surface is planned for the beginning of October 2018. MASCOT has been developed by the German Aerospace Center (DLR) in cooperation with the Centre National d’Etudes Spatiales (CNES). The main objective of MASCOT is to perform in-situ investigations of the asteroid surface and to support the sampling site selection for the mother spacecraft. Mascot is equipped with four scientific instruments a wide angle camera, a hyperspectral infrared microscope, a radiometer and a magnetometer. The camera (MasCam) provides ground truth for the orbital measurements of the Hayabusa2 orbiter instruments and the in-situ MASCOT sensor suite as well as geological context of the samples. The radiometer (MARA) determines the surface brightness temperature, the thermal inertia of the surface material and the spectral slope in infrared. The radiometer field of view is correlated with the wide angle camera field of view. The magnetometer (MasMAG) observes the magnetic field profile during descent and bouncing and determines any global and local magnetization of the asteroid.
Published: 2018
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27. On deviations from free-radial outflow in the inner coma of comet 67P/Churyumov–Gerasimenko

Author: Olivier Groussin, Björn Davidsson, Giampiero Naletto, S. Fornasier, Cecilia Tubiana, Horst Uwe Keller, P. L. Lamy, Michael Küppers, J.F. Wu, Hans Rickman, M. A. Barucci, W-H. Ip, Ekkehard Kührt, Stubbe F. Hviid, Selina-Barbara Gerig, L. M. Lara, C. C. Su, Marco Fulle, Nilda Oklay, R. Rodrigo, Monica Lazzarin, Stefano Mottola, Jean-Baptiste Vincent, V. Da Deppo, Laurent Jorda, Jörg Knollenberg, P. J. Gutierrez, Stefano Debei, Frank Scholten, G. Cremonese, M. De Cecco, Holger Sierks, Frank Preusker, J. L. Bertaux, Cesare Barbieri, Jakob Deller, Raphael Marschall, Dennis Bodewits, J. J. Lopez Moreno, Ivano Bertini, Detlef Koschny, Nicolas Thomas, Carsten Güttler, Jessica Agarwal, Imre Tóth, Francesco Marzari, J.-R. Kramm, Swiss National Science Foundation, European Commission, Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Università degli Studi di Padova = University of Padua (Unipd), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Operations Department (ESAC), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Department of Mechanical Engineering [NCTU], National Chiao Tung University (NCTU), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Dipartimento di Fisica e Astronomia 'Galileo Galilei', PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Physics and Astronomy [Uppsala], Uppsala University, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Padova (OAPD), Laboratory for Ultraviolet and X-ray Optical Research [Padova] (LUXOR), CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR)-National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), University of Trento [Trento], Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Universität Bern [Bern], Institute of Space Science [Taiwan], Max-Planck-Institut für Sonnensystemforschung (MPS), Max Planck Institute for Solar System Research (MPS), DLR Institute of Planetary Research, German Aerospace Center (DLR), University of Bern (UBERN), International Space Science Institute (ISSI), Centro Interdipartimentale di Studi e Attività Spaziali 'Giuseppe Colombo', Università di Padova (CISAS), Department of Astronomy, University of Maryland, Jet Propulsion Laboratory, California Institute of Technology (JPL), INAF - Osservatorio Astronomico, Via Tiepolo 11, 34014 Trieste, Italy, Graduate Institute of Astronomy, Institute for Geophysics and Extraterrestrial Physics, Technische Universität Braunschweig, Science Operations Department, European Space Astronomy Centre/ESA, P.O. Box 78, 28691 Villanueva de la Canada, Madrid, Spain, Deutsches Zentrum für Luft- und Raumfahrt (DLR), Department of Physics, National Tsing Hua University, Konkoly Observatory, Research Center for Astronomy and Earth Sciences, Max-Planck-Institut fur Sonnensystemforschung, Justus-von-Liebig-Weg, 3, 37077 Gottingen, Germany, Department of Physics and Astronomy, University of Padova, Vicolo dell'Osservatorio 3, 35122 Padova, Italy, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), European Space Agency (ESA), Space Research Center, Polish Academy of Sciences (Warsaw), Observatoire de Paris, Université Paris sciences et lettres (PSL), CNR-IFN UOS Padova LUXOR, Università di Trento (UNITN), Instituto de Astrofisica de Andalucia, CSIC (IAA), Dipartimento di Fisica, Università di Padova, Universita degli Studi di Padova, California Institute of Technology (CALTECH)-NASA, European Space Agency (ESA)-European Space Agency (ESA), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Consiglio Nazionale delle Ricerche [Roma] (CNR)-Consiglio Nazionale delle Ricerche [Roma] (CNR), Technische Universität Braunschweig [Braunschweig], Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), IMPEC - LATMOS, Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), Polska Akademia Nauk (PAN), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and Consejo Superior de Investigaciones Científicas [Spain] (CSIC)
Subjects: 67P/Churyumov-Gerasimenko, Brightness, 010504 meteorology & atmospheric sciences, Infrared, 67P/Churyumov–Gerasimenko, Astrophysics, Dust, Inner coma, OSIRIS, Rosetta, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Magnetosphere particle motion, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 520 Astronomy, Astronomy and Astrophysics, 620 Engineering, Particle acceleration, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Outflow, Direct simulation Monte Carlo, Astrophysics::Earth and Planetary Astrophysics, Test particle, Impact parameter, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: This article is available under the Creative Commons CC-BY-NC-ND license and permits non-commercial use of the work as published, without adaptation or alteration provided the work is fully attributed. For commercial reuse, permission must be requested below., The Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) onboard the European Space Agency's Rosetta spacecraft acquired images of comet 67P/Churyumov–Gerasimenko (67P) and its surrounding dust coma starting from May 2014 until September 2016. In this paper we present methods and results from analysis of OSIRIS images regarding the dust outflow in the innermost coma of 67P. The aim is to determine the global dust outflow behaviour and place constraints on physical processes affecting particles in the inner coma. We study the coma region right above the nucleus surface, spanning from the nucleus centre out to a distance of about 50 km comet centric distance (approximately 25 average comet radii). We primarily adopt an approach used by Thomas and Keller (1990) to study the dust outflow. We present the effects on azimuthally-averaged values of the dust reflectance of non-radial flow and non-point-source geometry, acceleration of dust particles, sublimation of icy dust particles after ejection from the surface, dust particle fragmentation, optical depth effects and the influence of gravitationally bound particles. All of these physical processes could modify the observed distribution of light scattered by the dust coma. In the image analysis, profiles of azimuthally averaged dust brightness as a function of impact parameter b (azimuthal average, “Ā-curve”) were fitted with a simple function that best fits the shape of our profile curves (f(b;u,v,w,z)=u/b+wb+z). The analytical fit parameters (u, v, w, z), which hold the key information about the dust outflow behaviour, were saved in a comprehensive database. Through statistical analysis of these information, we show that the spatial distribution of dust follows free-radial outflow behaviour (i.e. force-free radial outflow with constant velocity) beyond distances larger than ∼11.9 km from the comet centre, which corresponds to a relative distance of about 6 average comet radii from the comet centre. Hence, we conclude that beyond this distance, and on average, fragmentation and gravitationally bound particles are negligible processes in determining the optically scattered light distribution in the innermost coma. Closer to the nucleus we observe dust outflow behaviour that deviates from free-radial outflow. A comparison of our result profiles with numerical models using a Direct Simulation Monte Carlo (DSMC) approach with dust particle distributions calculated using a test particle approach has been used to demonstrate the influence of a complex shape and particle acceleration on the azimuthal average profiles. We demonstrate that, while other effects such as fragmentation or sublimation of dust particles cannot be ruled out, acceleration of the dust particles and effects arising from the shape of the irregular nucleus (non-point source geometry) are sufficient to explain the observed dust outflow behaviour from image data analysis. As a by-product of this work, we have calculated “Afρ” values for the 1/r regime. We found a peak in the coma activity in terms of Afρ (normalised to a phase angle of 90°) of ∼210 cm 20 days after perihelion. Furthermore, based on simplified models of particle motion within bound orbits, it is shown that limits on the total cross-sectional area of bound particles might be derived through further analysis. An example is given. © 2018 The Authors, The team from the University of Bern is supported through the Swiss National Science Foundation and through the NCCR PlanetS. The project has also received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No. 686709. This work was supported by the Swiss State Secretariat for Education, Research and Innovation (SERI) under contract number 16.0008-2. The opinions expressed and arguments employed herein do not necessarily reflect the official views of the Swiss Government.
Published: 2018
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28. The big lobe of 67P/Churyumov–Gerasimenko comet: morphological and spectrophotometric evidences of layering as from OSIRIS data

Author: P. J. Gutierrez, Xian Shi, Carsten Güttler, Pedro Hasselmann, J. J. López-Moreno, Matteo Massironi, Monica Lazzarin, Detlef Koschny, Stubbe F. Hviid, M. A. Barucci, Björn Davidsson, Cecilia Tubiana, Ivano Bertini, Pamela Cambianica, Nicolas Thomas, Michael Küppers, Francesca Ferri, Luca Penasa, Francesco Marzari, M. De Cecco, W-H. Ip, J. L. Bertaux, Marco Franceschi, Laurent Jorda, Holger Sierks, J.-B. Vincent, Olivier Groussin, E. Frattin, F. La Forgia, Stefano Debei, Philippe Lamy, Jakob Deller, Maurizio Pajola, Nilda Oklay, Giampiero Naletto, Ekkehard Kührt, Sonia Fornasier, L. M. Lara, V. Da Deppo, Marco Fulle, Jörg Knollenberg, Emanuele Simioni, Sabrina Ferrari, R. Rodrigo, Gabriele Cremonese, Alice Lucchetti, H. U. Keller, Dennis Bodewits, Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Universita degli Studi di Padova, Dipartimento di Fisica e Astronomia 'Galileo Galilei', CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Fundacion Galileo Galilei, Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, CNR Institute for Photonics and Nanotechnologies (IFN), Department of Industrial Engineering [Padova], Dipartimento di Geoscienze [Padova], INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Operations Department (ESAC), European Space Astronomy Centre (ESAC), Physikalisches Institut [Bern], Universität Bern [Bern], Center for Space and Habitability (CSH), University of Bern, German Centre for Air and Space Travel, Centre National D'Etudes Spatiales (France), Agenzia Spaziale Italiana, Agencia Estatal de Investigación (España), European Space Agency, Swedish National Space Agency, Ferrari, Sabrina, Penasa, L., La Forgia, F., Massironi, M., Naletto, G., Lazzarin, M., Fornasier, S., Hasselmann, P. H., Lucchetti, A., Pajola, M., Ferri, F., Cambianica, Pamela, Oklay, N., Tubiana, C., Sierks, H., Lamy, P. L., Rodrigo, R., Koschny, D., Davidsson, B., Barucci, M. A., Bertaux, J. -L., Bertini, I., Bodewits, D., Cremonese, G., Da Deppo, V., Debei, S., De Cecco, M., Deller, J., Franceschi, M., Frattin, Elisa, Fulle, M., Groussin, O., Gutiérrez, P. J., Güttler, C., Hviid, S. F., Ip, W. -H., Jorda, L., Keller, H. U., Knollenberg, J., Kührt, E., Küppers, M., Lara, L. M., López-Moreno, J. J., Marzari, F., Shi, X., Simioni, E., Thomas, N., Vincent, J. -B., Università degli Studi di Padova = University of Padua (Unipd), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), NASA-California Institute of Technology (CALTECH), Universität Bern [Bern] (UNIBE), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), IMPEC - LATMOS, Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), and Technische Universität Braunschweig [Braunschweig]
Subjects: 67P/Churyumov-Gerasimenko, Brightness, Comets: general, Comets: individual: 67P/Churyumov-Gerasimenko, Methods: data analysis, Techniques: image processing, Astronomy and Astrophysics, Space and Planetary Science, 010504 meteorology & atmospheric sciences, Multispectral image, Comet, Data analysis, Mineralogy, Spatial distribution, 01 natural sciences, Texture (geology), Image processing, individual: 67P/Churyumov-Gerasimenko [Comets], 0103 physical sciences, medicine, Comets, image processing [Techniques], spectral variegation, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, [PHYS]Physics [physics], biology, OSIRIS cameras, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 520 Astronomy, general [Comets], Astronomy and Astrophysic, biology.organism_classification, 620 Engineering, Lobe, data analysi [Methods], medicine.anatomical_structure, multiple-filters, Variegation (histology), Osiris
Abstract: Between 2014 and 2016, ESA's Rosetta OSIRIS cameras acquired multiple-filters images of the layered nucleus of comet 67P/Churyumov-Gerasimenko, ranging from ultraviolet to near-infrared wavelengths. No correlation between layers disposition and surface spectral variegation has been observed so far. This paper investigates possible spectral differences among decametre-thickness outcropping layers of the biggest lobe of the comet by means of OSIRIS image dataset. A two-classes maximum likelihood classification was applied on consolidated outcrops and relative deposits identified on post-perihelion multispectral images of the big lobe. We distinguished multispectral data on the basis of the structural elevation of the onion-shell Ellipsoidal Model of 67P. The spatial distribution of the two classes displays a clear dependence on the structural elevation, with the innermost class resulting over 50 per cent brighter than the outermost one. Consolidated cometarymaterials located at different structural levels are characterized by different brightness and revealed due to the selective removal of large volumes. This variegation can be attributed to a different texture of the outcrop surface and/or to a different content of refractory materials.© 2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society., We are grateful to Paul Helfenstein for corrections that improved our paper. OSIRIS was built by a consortium of the Max-Planck-Institut fur Sonnensystemforschung, in Goottingen, Germany, CISAS-University of Padova, Italy, the Laboratoire d'Astrophysique de Marseille, France, the Instituto de Astrofisica de Andalucia, CSIC, Granada, Spain, the Research and Scientific Support Department of the European Space Agency, Noordwijk, The Netherlands, the Instituto Nacional de Tecnica Aeroespacial, Madrid, Spain, the Universidad Politechnica de Madrid, Spain, the Department of Physics and Astronomy of Uppsala University, Sweden, and the Institut fur Datentechnik und Kommunikationsnetze der Technischen Universitat Braunschweig, Germany. The support of the national funding agencies of Germany (DLR), Italy (ASI), France (CNES), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged. We thank the ESA teams at ESAC, ESOC, and ESTEC for their work in support of the Rosetta mission.
Published: 2018
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29. Regional unit definition for the nucleus of comet 67P/Churyumov-Gerasimenko on the SHAP7 model

Author: Holger Sierks, J.-B. Vincent, F. Preusker, Giampiero Naletto, Francesco Marzari, Sonia Fornasier, Stubbe F. Hviid, M. A. Barucci, P. J. Gutierrez, Carsten Güttler, J. J. Lopez-Moreno, Jörg Knollenberg, Ivano Bertini, Stefano Debei, V. Da Deppo, P. L. Lamy, Frank Scholten, Detlef Koschny, Björn Davidsson, W-H. Ip, Marco Fulle, Nicolas Thomas, M. R. El Maarry, Cecilia Tubiana, Monica Lazzarin, Ekkehard Kührt, L. M. Lara, Raphael Marschall, J. L. Bertaux, H. U. Keller, Dennis Bodewits, R. Rodrigo, Laurent Jorda, G. Cremonese, M. De Cecco, P. Theologou, Olivier Groussin, ITA, USA, GBR, FRA, DEU, Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), International Space Science Institute [Bern] (ISSI), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Università degli Studi di Padova = University of Padua (Unipd), Dipartimento di Fisica e Astronomia 'Galileo Galilei', CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Institute for Photonics and Nanotechnologies (IFN), Department of Industrial Engineering [Padova], University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Universität Bern [Bern], Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Universita degli Studi di Padova, Consiglio Nazionale delle Ricerche [Roma] (CNR), Max-Planck-Institut für Sonnensystemforschung (MPS), European Space Agency (ESA)-European Space Agency (ESA), California Institute of Technology (CALTECH)-NASA, Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), IMPEC - LATMOS, Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Technische Universität Braunschweig [Braunschweig], Swiss National Science Foundation, European Commission, and State Secretariat for Education, Research and Innovation (Switzerland)
Subjects: 67P/Churyumov-Gerasimenko, Morphology, Surface (mathematics), 010504 meteorology & atmospheric sciences, Comet, Geometry, Surface finish, Table (information), 01 natural sciences, Nucleus, Computer graphics, Rosetta, 0103 physical sciences, medicine, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Subdivision, Astronomy and Astrophysics, Space and Planetary Science, business.industry, 520 Astronomy, 620 Engineering, medicine.anatomical_structure, es, [SDU]Sciences of the Universe [physics], business, Unit (ring theory), Geology
Abstract: Open Acces publication. This article is available under the Creative Commons CC-BY-NC-ND license and permits non-commercial use of the work as published, without adaptation or alteration provided the work is fully attributed., The previously defined regions on the nucleus of comet 67P/Churyumov-Gerasimenko have been mapped back onto the 3D SHAP7 model of the nucleus (Preusker et al., 2017). The resulting regional definition is therefore self-consistent with boundaries that are well defined in 3 dimensions. The facets belonging to each region are provided as supplementary material. The shape model has then been used to assess inhomogeneity of nucleus surface morphology within individual regions. Several regions show diverse morphology. We propose sub-division of these regions into clearly identifiable units (sub-regions) and a comprehensive table is provided. The surface areas of each sub-region have been computed and statistics based on grouping of unit types are provided. The roughness of each region is also provided in a quantitative manner using a technique derived from computer graphics applications. The quantitative method supports the sub-region definition by showing that differences between sub-regions can be numerically justified.© 2018 The Authors, The team from the University of Bern is supported through the Swiss National Science Foundation and through the NCCR PlanetS. The project has also received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 686709. This work was supported by the Swiss State Secretariat for Education, Research and Innovation (SERI) under contract number 16.0008-2.
Published: 2018
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30. Coma morphology of comet 67P controlled by insolation over irregular nucleus

Author: Nilda Oklay, Jessica Agarwal, V. Da Deppo, M. De Cecco, Philippe Lamy, J.-B. Vincent, Laurent Jorda, G. Cremonese, X. Hu, Steve Boudreault, Carsten Güttler, M. A. Barucci, W-H. Ip, Marco Fulle, M. Rose, Imre Toth, Stefano Debei, Detlef Koschny, Sonia Fornasier, Ekkehard Kührt, Cesare Barbieri, L. M. Lara, Jakob Deller, P. J. Gutierrez, Francesco Marzari, Holger Sierks, Xian Shi, Jörg Knollenberg, Stefano Mottola, Maurizio Pajola, Géza Kovács, R. Rodrigo, Giampiero Naletto, J. J. López-Moreno, Olivier Groussin, J.-R. Kramm, Jean-Loup Bertaux, Dennis Bodewits, H. U. Keller, Ivano Bertini, Michael Küppers, Stubbe F. Hviid, Björn Davidsson, Cecilia Tubiana, Monica Lazzarin, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], PI-DSMC software package, INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), NASA Ames Research Center (ARC), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Dipartimento di Fisica e Astronomia 'Galileo Galilei', Università degli Studi di Padova = University of Padua (Unipd), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Department of Industrial Engineering [Padova], University of Trento [Trento], Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), European Space Astronomy Centre (ESAC), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Dipartimento di Fisica [Politecnico Milano] (POLIMI), Politecnico di Milano [Milan] (POLIMI), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), German Centre for Air and Space Travel, Centre National D'Etudes Spatiales (France), Agenzia Spaziale Italiana, Agencia Estatal de Investigación (España), European Space Agency, Swedish National Space Agency, Max-Planck-Institut für Sonnensystemforschung (MPS), Universita degli Studi di Padova, Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), European Space Agency (ESA), Consiglio Nazionale delle Ricerche [Roma] (CNR), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Dipartimento di Fisica [Politecnico Milano], Technische Universität Braunschweig [Braunschweig], PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), IMPEC - LATMOS, Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), and Dipartimento di Fisica [Milano]
Subjects: Brightness, 010504 meteorology & atmospheric sciences, Comet, structural complexity, Coma (optics), Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, cometary comae, dust jets, 0103 physical sciences, Rosetta, medicine, Sunrise, surface, Surface layer, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, Spacecraft, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], business.industry, Astronomy and Astrophysics, dust coma, Outgassing, medicine.anatomical_structure, 13. Climate action, Astrophysics::Earth and Planetary Astrophysics, business, Nucleus, Comet 67/P
Abstract: While the structural complexity of cometary comae is already recognizable from telescopic observations, the innermost region, within a few radii of the nucleus, was not resolved until spacecraft exploration became a reality. The dust coma displays jet-like features of enhanced brightness superposed on a diffuse background . Some features can be traced to specific areas on the nucleus, and result conceivably from locally enhanced outgassing and/or dust emission. However, diffuse or even uniform activity over topographic concavity can converge to produce jet-like features. Therefore, linking observed coma morphology to the distribution of activity on the nucleus is difficult. Here, we study the emergence of dust activity at sunrise on comet 67P/Churyumov-Gerasimenko using high-resolution, stereo images from the OSIRIS camera onboard the Rosetta spacecraft, where the sources and formation of the jet-like features are resolved. We perform numerical simulations to show that the ambient dust coma is driven by pervasive but non-uniform water outgassing from the homogeneous surface layer. Physical collimations of gas and dust flows occur at local maxima of insolation and also via topographic focusing. Coma structures are projected to exhibit jet-like features that vary with the perspective of the observer. For an irregular comet such as 67P/Churyumov-Gerasimenko, near-nucleus coma structures can be concealed in the shadow of the nucleus, which further complicates the picture.© 2018 The Author(s)., OSIRIS was built by a consortium led by the Max-Planck-Institut fur Sonnensystemforschung, Gottingen, Germany, in collaboration with CISAS, University of Padova, Italy, the Laboratoire d'Astrophysique de Marseille, France, the Instituto de Astrofisica de Andalucia, CSIC, Granada, Spain, the Scientific Support Office of the European Space Agency, Noordwijk, The Netherlands, the Instituto Nacional de Tecnica Aeroespacial, Madrid, Spain, the Universidad Politechnica de Madrid, Spain, the Department of Physics and Astronomy of Uppsala University, Sweden, and the Institut fur Datentechnik und Kommunikationsnetze der Technischen Universitat Braunschweig, Germany. The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB) and the ESA Technical Directorate is gratefully acknowledged.
Published: 2018
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31. The phase function and density of the dust observed at comet 67P/Churyumov-Gerasimenko

Author: P. J. Gutierrez, W-H. Ip, F. Moreno, Monica Lazzarin, F. La Forgia, Ivano Bertini, Xian Shi, V. Da Deppo, Cesare Barbieri, Stefano Mottola, Holger Sierks, Giampiero Naletto, Pasquale Palumbo, M. A. Barucci, Jakob Deller, Stavro Ivanovski, H. S. Hviid, J. Lasue, Giovanna Rinaldi, Marco Fulle, Michael Küppers, Philippe Lamy, Hans Rickman, Stefano Debei, Ekkehard Kührt, Alessandra Rotundi, Detlef Koschny, Nicolas Thomas, R. Rodrigo, M. De Cecco, J.-R. Kramm, Björn Davidsson, Cecilia Tubiana, Laurent Jorda, G. Cremonese, Carsten Güttler, J. L. Bertaux, Anny Chantal Levasseur-Regourd, M. L. Lara, Olivier Groussin, Sonia Fornasier, Jörg Knollenberg, V. Della Corte, J. J. López-Moreno, H. U. Keller, Francesco Marzari, Dennis Bodewits, Agenzia Spaziale Italiana, INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), Helmholtz zentrum für Schwerionenforschung GmbH (GSI), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Dipartimento di Scienze e Tecnologie [Napoli] (DIST), Universita degli studi di Napoli 'Parthenope' [Napoli], Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Department of Physics and Astronomy [Uppsala], Uppsala University, Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, INAF - Osservatorio Astronomico di Padova (OAPD), Laboratory for Ultraviolet and X-ray Optical Research [Padova] (LUXOR), CNR Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR)-Consiglio Nazionale delle Ricerche [Roma] (CNR), Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Department of Industrial Engineering [Padova], University of Trento [Trento], Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], European Space Astronomy Centre (ESAC), Physikalisches Institut [Bern], Universität Bern [Bern], Università degli Studi di Padova = University of Padua (Unipd), Università degli Studi di Napoli 'Parthenope' = University of Naples (PARTHENOPE), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Agence Spatiale Européenne = European Space Agency (ESA), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR)-National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), NASA-California Institute of Technology (CALTECH), Universität Bern [Bern] (UNIBE), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), IMPEC - LATMOS, Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), Polska Akademia Nauk (PAN), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Technische Universität Braunschweig [Braunschweig], INAF - Osservatorio Astronomico di Trieste ( OAT ), Istituto Nazionale di Astrofisica ( INAF ), Istituto di Astrofisica e Planetologia Spaziali ( IAPS ), Dipartimento di Scienze e Tecnologie [Napoli] ( DIST ), Max-Planck-Institut für Sonnensystemforschung ( MPS ), Institut de recherche en astrophysique et planétologie ( IRAP ), Université Paul Sabatier - Toulouse 3 ( UPS ) -Observatoire Midi-Pyrénées ( OMP ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire Atmosphères, Milieux, Observations Spatiales ( LATMOS ), Université de Versailles Saint-Quentin-en-Yvelines ( UVSQ ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Versailles Saint-Quentin-en-Yvelines ( UVSQ ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Instituto de Astrofísica de Andalucía ( IAA ), Consejo Superior de Investigaciones Científicas [Spain] ( CSIC ), Deutsches Zentrum für Luft- und Raumfahrt [Berlin] ( DLR ), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' ( CISAS ), Laboratoire d'Astrophysique de Marseille ( LAM ), Aix Marseille Université ( AMU ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National d'Etudes Spatiales ( CNES ) -Centre National de la Recherche Scientifique ( CNRS ), Centro de Astrobiologia [Madrid] ( CAB ), Instituto Nacional de Técnica Aeroespacial ( INTA ) -Consejo Superior de Investigaciones Científicas [Spain] ( CSIC ), International Space Science Institute ( ISSI ), European Space Research and Technology Centre ( ESTEC ), European Space Agency ( ESA ), Space Research Centre [Warsaw] ( CBK ), Polska Akademia Nauk ( PAN ), Laboratoire d'études spatiales et d'instrumentation en astrophysique ( LESIA ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire de Paris-Université Paris Diderot - Paris 7 ( UPD7 ) -Centre National de la Recherche Scientifique ( CNRS ), INAF - Osservatorio Astronomico di Padova ( OAPD ), Laboratory for Ultraviolet and X-ray Optical Research [Padova] ( LUXOR ), CNR Institute for Photonics and Nanotechnologies ( IFN ), Consiglio Nazionale delle Ricerche [Roma] ( CNR ) -Consiglio Nazionale delle Ricerche [Roma] ( CNR ), Jet Propulsion Laboratory ( JPL ), NASA-California Institute of Technology ( CALTECH ), National Central University [Taiwan] ( NCU ), Space Science Institute [Macau] ( SSI ), Macau University of Science and Technology ( MUST ), Aix Marseille Université ( AMU ), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] ( IGEP ), and European Space Astronomy Center ( ESAC )
Subjects: 67P/Churyumov-Gerasimenko, Brightness, comets: individual: 67P/Churyumov- Gerasimenko, 010504 meteorology & atmospheric sciences, Comet, Dust particles, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, space vehicles, comets: general, comets: individual: 67P/Churyumov-Gerasimenko, 01 natural sciences, Astronomi, astrofysik och kosmologi, individual: 67P/Churyumov-Gerasimenko [Comets], 0103 physical sciences, Astronomy, Astrophysics and Cosmology, Phase function, Astrophysics::Solar and Stellar Astrophysics, comets, Particle density, 010303 astronomy & astrophysics, [ SDU.ASTR ] Sciences of the Universe [physics]/Astrophysics [astro-ph], Astrophysics::Galaxy Astrophysics, Comets: individual: 67P/Churyumov, Gerasimenko, 0105 earth and related environmental sciences, Physics, 520 Astronomy, comets: general, comets: individual: 67P/Churyumov-Gerasimenko, general [Comets], Astronomy and Astrophysics, Space vehicles, 620 Engineering, Bulk density, space vehicles, comets: general, comets: individual: 67P/Churyumov- Gerasimenko, Density distribution, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], space vehicles, Astrophysics::Earth and Planetary Astrophysics, Mass fraction
Abstract: The OSIRIS camera onboard Rosetta measured the phase function of both the coma dust and the nucleus. The two functions have a very different slope versus the phase angle. Here, we show that the nucleus phase function should be adopted to convert the brightness to the size of dust particles larger than 2.5 mm only. This makes the dust bursts observed close to Rosetta by OSIRIS, occurring about every hour, consistent with the fragmentation on impact with Rosetta of parent particles, whose flux agrees with the dust flux observed by GIADA. OSIRIS also measured the antisunward acceleration of the fragments, thus providing the first direct measurement of the solar radiation force acting on the dust fragments and thus of their bulk density, excluding any measurable rocket effect by the ice sublimation from the dust. The obtained particle density distribution has a peak matching the bulk density of most COSIMA particles, and represents a subset of the density distribution measured by GIADA. This implies a bias in the elemental abundances measured by COSIMA, which thus are consistent with the 67P dust mass fractions inferred by GIADA, i.e. (38 ± 8) per cent of hydrocarbons versus the (62 ± 8) per cent of sulphides and silicates.© 2018 The Author(s).Published by Oxford University Press on behalf of the Royal Astronomical Society., We thank the anonymous referee for having significantly improved the paper; and the Rosetta Science Ground Segment at ESAC, the Rosetta Mission Operations Centre at ESOC, and the Rosetta Project at ESTEC for their outstanding work enabling the science return of the Rosetta Mission. All GIADA data presented here are available on request before archiving in the PSA. This research was supported by the Italian Space Agency (ASI) within the ASI-INAF agreements I/032/05/0 and I/024/12/0.
Published: 2018
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32. Exposed bright features on the comet 67P/Churyumov-Gerasimenko: distribution and evolution

Author: J. L. Bertaux, L. Jorda, Carsten Güttler, Francesco Marzari, Monica Lazzarin, D. Bodewits, Holger Sierks, V. Da Deppo, Jörg Knollenberg, Nafiseh Masoumzadeh, Giampiero Naletto, Maurizio Pajola, H. U. Keller, Björn Davidsson, Ivano Bertini, Philippe Lamy, Steve Boudreault, O. Groussin, Detlef Koschny, Michael Küppers, Nicolas Thomas, Cecilia Tubiana, J. D. P. Deshapriya, Stefano Debei, M. De Cecco, J. J. Lopez Moreno, Sonia Fornasier, Xian Shi, J. B. Vincent, Stefano Mottola, Pedro J. Gutiérrez, L. M. Lara, Alice Lucchetti, M. A. Barucci, J. Rainer Kramm, R. Rodrigo, N. Oklay, Gabriele Cremonese, Stubbe F. Hviid, Pedro Hasselmann, H. V. Hoang, Marco Fulle, Hans Rickman, F. Preusker, W-H. Ip, Clement Feller, Ekkehard Kührt, Cesare Barbieri, Jakob Deller, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Universita degli Studi di Padova, NASA Ames Research Center (ARC), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Department of Physics and Astronomy [Uppsala], Uppsala University, Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Laboratory for Ultraviolet and X-ray Optical Research [Padova] (LUXOR), CNR Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR)-Consiglio Nazionale delle Ricerche [Roma] (CNR), Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Department of Industrial Engineering [Padova], University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], European Space Astronomy Centre (ESAC), Physikalisches Institut [Bern], Universität Bern [Bern], German Centre for Air and Space Travel, Centre National D'Etudes Spatiales (France), Agenzia Spaziale Italiana, Ministerio de Educación y Ciencia (España), European Space Agency, Swedish National Space Board, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), IMPEC - LATMOS, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), Polska Akademia Nauk (PAN), NASA-California Institute of Technology (CALTECH), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Technische Universität Braunschweig [Braunschweig], Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Università degli Studi di Padova = University of Padua (Unipd), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Agence Spatiale Européenne = European Space Agency (ESA), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR)-National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Universität Bern [Bern] (UNIBE), Laboratoire d'études spatiales et d'instrumentation en astrophysique ( LESIA ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire de Paris-Université Paris Diderot - Paris 7 ( UPD7 ) -Centre National de la Recherche Scientifique ( CNRS ), Max-Planck-Institut für Sonnensystemforschung ( MPS ), INAF - Osservatorio Astronomico di Padova ( OAPD ), Istituto Nazionale di Astrofisica ( INAF ), NASA Ames Research Center ( ARC ), Deutsches Zentrum für Luft- und Raumfahrt [Berlin] ( DLR ), Laboratoire Atmosphères, Milieux, Observations Spatiales ( LATMOS ), Université de Versailles Saint-Quentin-en-Yvelines ( UVSQ ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Versailles Saint-Quentin-en-Yvelines ( UVSQ ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Centro de Astrobiologia [Madrid] ( CAB ), Instituto Nacional de Técnica Aeroespacial ( INTA ) -Consejo Superior de Investigaciones Científicas [Spain] ( CSIC ), International Space Science Institute ( ISSI ), European Space Research and Technology Centre ( ESTEC ), European Space Agency ( ESA ), Space Research Centre [Warsaw] ( CBK ), Polska Akademia Nauk ( PAN ), Laboratory for Ultraviolet and X-ray Optical Research [Padova] ( LUXOR ), CNR Institute for Photonics and Nanotechnologies ( IFN ), Consiglio Nazionale delle Ricerche [Roma] ( CNR ) -Consiglio Nazionale delle Ricerche [Roma] ( CNR ), Jet Propulsion Laboratory ( JPL ), NASA-California Institute of Technology ( CALTECH ), INAF - Osservatorio Astronomico di Trieste ( OAT ), Laboratoire d'Astrophysique de Marseille ( LAM ), Aix Marseille Université ( AMU ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National d'Etudes Spatiales ( CNES ) -Centre National de la Recherche Scientifique ( CNRS ), Instituto de Astrofísica de Andalucía ( IAA ), Consejo Superior de Investigaciones Científicas [Spain] ( CSIC ), National Central University [Taiwan] ( NCU ), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] ( IGEP ), European Space Astronomy Center ( ESAC ), and Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' ( CISAS )
Subjects: 010504 meteorology & atmospheric sciences, Comet, Data analysis, 67P/Churyumov–Gerasimenko, Context (language use), Astrophysics, 01 natural sciences, individual: 67P/Churyumov-Gerasimenko [Comets], Methods: data analysis, 0103 physical sciences, Comets: individual: 67P/Churyumov-Gerasimenko, Techniques: photometric, Photometric techniques, data analysis [Methods], 010303 astronomy & astrophysics, [ SDU.ASTR ] Sciences of the Universe [physics]/Astrophysics [astro-ph], 0105 earth and related environmental sciences, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], biology, photometric [Techniques], Astronomy, Astronomy and Astrophysics, Albedo, biology.organism_classification, Reflectivity, On board, 13. Climate action, Space and Planetary Science, Osiris
Abstract: Context. Since its arrival at the comet 67P/Churyumov-Gerasimenko in August 2014, the Rosetta spacecraft followed the comet as it went past the perihelion and beyond until September 2016. During this time there were many scientific instruments operating on board Rosetta to study the comet and its evolution in unprecedented detail. In this context, our study focusses on the distribution and evolution of exposed bright features that have been observed by OSIRIS, which is the scientific imaging instrument aboard Rosetta. Aims. We envisage investigating various morphologies of exposed bright features and the mechanisms that triggered their appearance. Methods. We co-registered multi-filter observations of OSIRIS images that are available in reflectance. The Lommel-Seeliger disk function was used to correct for the illumination conditions and the resulting colour cubes were used to perform spectrophotometric analyses on regions of interest. Results. We present a catalogue of 57 exposed bright features observed on the nucleus of the comet, all of which are attributed to the presence of HO ice on the comet. Furthermore, we categorise these patches under four different morphologies and present geometric albedos for each category. Conclusions. Although the nucleus of 67P/Churyumov-Gerasimenko appears to be dark in general, there are localised HO ice sources on the comet. Cometary activity escalates towards the perihelion passage and reveals such volatile ices. We propose that isolated HO ice patches found in smooth terrains in regions, such as Imhotep, Bes, and Hapi, result from frost as an aftermath of the cessation of the diurnal water cycle on the comet as it recedes from perihelion. Upon the comet's return to perihelion, such patches are revealed when sublimation-driven erosion removes the thin dust layers that got deposited earlier. More powerful activity sources such as cometary outbursts are capable of revealing much fresher, less contaminated HO ice that is preserved with consolidated cometary material, as observed on exposed patches resting on boulders. This is corroborated by our albedo calculations that attribute higher albedos for bright features with formations related to outbursts.© ESO 2018., The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged.
Published: 2018
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33. Tensile strength of 67P/Churyumov-Gerasimenko nucleus material from overhangs (Corrigendum)

Author: A. T. Auger, Stubbe F. Hviid, Michael Küppers, Imre Toth, Ekkehard Kührt, Sonia Fornasier, Björn Davidsson, Simone Marchi, F. Scholten, M. A. Barucci, Cecilia Tubiana, Jörg Knollenberg, R. Rodrigo, Yann Brouet, W-H. Ip, P. Lamy, Monica Lazzarin, Paul Hartogh, Nicholas Attree, D. Nébouy, Francesco Marzari, Steve Boudreault, Ivano Bertini, P. J. Gutierrez, Detlef Koschny, Mohamed Ramy El-Maarry, Marco Fulle, L. M. Lara, Hans Rickman, F. Preusker, Holger Sierks, Nicolas Thomas, V. Da Deppo, Stephen C. Lowry, Giampiero Naletto, Cesare Barbieri, Jakob Deller, Géza Kovács, N. Oklay, J. J. Lopez Moreno, Stefano Debei, J.-R. Kramm, Maurizio Pajola, M. F. A'Hearn, Olivier Groussin, J. L. Bertaux, Carsten Güttler, M. De Cecco, Laurent Jorda, Dennis Bodewits, G. Cremonese, Xian Shi, H. U. Keller, J. B. Vincent, Stefano Mottola, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Dipartimento di Fisica e Astronomia 'Galileo Galilei', Università degli Studi di Padova = University of Padua (Unipd), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), ESA Scientific Support Office, Agence Spatiale Européenne = European Space Agency (ESA), Department of Astronomy and Space Physics [Uppsala], Uppsala University, Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Department of Industrial Engineering [Padova], Università degli Studi di Trento (UNITN), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Operations Department (ESAC), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Centre for Astrophysics and Planetary Science [Canterbury] (CAPS), University of Kent [Canterbury], Southwest Research Institute [Boulder] (SwRI), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), NASA Ames Research Center (ARC), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), ITA, USA, GBR, FRA, and DEU
Subjects: Physics, 67P/Churyumov-Gerasimenko, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], comets: general, 520 Astronomy, Astronomy and Astrophysics, Astrophysics, 620 Engineering, Methods observational, medicine.anatomical_structure, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Ultimate tensile strength, comets: general / comets: individual: Churyumov-Gerasimenko / methods: observational / errata, medicine, comets, Composite material, methods: observational, Nucleus, addenda, comets: individual: Churyumov-Gerasimenko, errata, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2018
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34. Fractures on comet 67P/Churyumov-Gerasimenko observed by Rosetta/OSIRIS

Author: H. U. Keller, Carsten Güttler, M. A. Barucci, Ivano Bertini, A. T. Auger, Matteo Massironi, M. De Cecco, Simone Marchi, Stubbe F. Hviid, Raphael Marschall, Mohamed Ramy El-Maarry, Frank Scholten, Maurizio Pajola, Cesare Barbieri, Hans Rickman, R. Rodrigo, Jörg Knollenberg, Stefano Mottola, Jakob Deller, Marco Fulle, Michael Küppers, A. Gracia-Berná, Nilda Oklay, W-H. Ip, V. Da Deppo, P. J. Gutiérrez, Laurent Jorda, Holger Sierks, Sonia Fornasier, Jean-Loup Bertaux, J.-B. Vincent, Harald Michalik, Olivier Groussin, Antoine Pommerol, Marc Hofmann, Frank Preusker, Detlef Koschny, Nicolas Thomas, J.-R. Kramm, Monica Lazzarin, B. J. R. Davidsson, Philippe Lamy, Ekkehard Kührt, Cecilia Tubiana, L. M. Lara, Francesco Marzari, J. J. Lopez Moreno, Michael F. A'Hearn, Gabriele Cremonese, Stefano Debei, S. Höfner, Géza Kovács, and Giampiero Naletto
Subjects: Insolation, Physics, 010504 meteorology & atmospheric sciences, biology, Comet, Diurnal temperature variation, Weathering, Geophysics, biology.organism_classification, 01 natural sciences, Thermal contraction, Astrobiology, 13. Climate action, 0103 physical sciences, General Earth and Planetary Sciences, Osiris, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: The OSIRIS experiment onboard the Rosetta spacecraft currently orbiting comet 67P/Churyumov-Gerasimenko has yielded unprecedented views of a comet's nucleus. We present here the first ever observations of meter-scale fractures on the surface of a comet. Some of these fractures form polygonal networks. We present an initial assessment of their morphology, topology, and regional distribution. Fractures are ubiquitous on the surface of the comet's nucleus. Furthermore, they occur in various settings and show different topologies suggesting numerous formation mechanisms, which include thermal insolation weathering, orbital-induced stresses, and possibly seasonal thermal contraction. However, we conclude that thermal insolation weathering is responsible for creating most of the observed fractures based on their morphology and setting in addition to thermal models that indicate diurnal temperature ranges exceeding 200 K and thermal gradients of ~15 K/min at perihelion are possible. Finally, we suggest that fractures could be a facilitator in surface evolution and long-term erosion.
Published: 2015
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35. MERTIS: the thermal infrared imaging spectrometer onboard of the Mercury Planetary Orbiter

Author: Jörg Knollenberg, Ingo Walter, Jörn Helbert, Andreas Gebhardt, T. Zeh, G. Peter, Iris Weber, Harry Hiesinger, and E. Kopp
Subjects: Orbiter, Materials science, Planet, law, Detector, Imaging spectrometer, Thermal emittance, Astrophysics::Earth and Planetary Astrophysics, Surface layer, Spectral resolution, Image resolution, Remote sensing, law.invention
Abstract: The MERTIS instrument is a thermal infrared imaging spectrometer onboard of ESA’s cornerstone mission BepiColombo to Mercury. MERTIS has four goals: the study of Mercury’s surface composition, identification of rock-forming minerals, mapping of the surface mineralogy, and the study of the surface temperature variations and thermal inertia. MERTIS will provide detailed information about the mineralogical composition of Mercury’s surface layer by measuring the spectral emittance in the spectral range from 7-14 μm at high spatial and spectral resolution. Furthermore MERTIS will obtain radiometric measurements in the spectral range from 7-40 μm to study the thermo-physical properties of the surface material. The MERTIS detector is based on an uncooled micro-bolometer array providing spectral separation and spatial resolution according to its 2-dimensional shape. The operation principle is characterized by intermediate scanning of the planet surface and three different calibration targets – free space view and two on-board black body sources. In the current project phase, the MERTIS Qualification Model (QM) is under a rigorous testing program. Besides a general overview of the instrument principles, the papers addresses major aspects of the instrument design, manufacturing and verification.
Published: 2017
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36. A three-dimensional modelling of the layered structure of comet 67P/Churyumov-Gerasimenko

Author: Hans Rickman, Matteo Massironi, J.-R. Kramm, Ivano Bertini, Stubbe F. Hviid, Francesco Marzari, P. J. Gutierrez, M. De Cecco, Emanuele Simioni, Ekkehard Kührt, L. M. Lara, Frank Scholten, Detlef Koschny, Cesare Barbieri, Maurizio Pajola, R. Rodrigo, V. Da Deppo, Jakob Deller, Frank Preusker, S. Fornasier, Monica Lazzarin, Jean-Baptiste Vincent, Giampiero Naletto, Francesca Ferri, Robert Gaskell, Jessica Agarwal, Wing-Huen Ip, J-C. Lee, Laurent Jorda, N. Thomas, M. A. Barucci, Björn Davidsson, Michael Küppers, Alice Lucchetti, M. F. A'Hearn, Clement Feller, Marc Hofmann, Cecilia Tubiana, Olivier Groussin, Stefano Debei, Gabriele Cremonese, Holger Sierks, Marco Fulle, Philippe Lamy, Sabrina Ferrari, J. J. Lopez Moreno, F. La Forgia, Nilda Oklay, Carsten Güttler, E. Frattin, Luca Penasa, J. L. Bertaux, H. U. Keller, Jörg Knollenberg, Xian Shi, Stefano Mottola, Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Università degli Studi di Padova = University of Padua (Unipd), Dipartimento di Astronomia [Padova], INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), NASA Ames Research Center (ARC), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Planetary Science Institute [Tucson] (PSI), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Department of Physics and Astronomy [Uppsala], Uppsala University, Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Department of Mechanical Engineering [Padova], Department of Industrial Engineering [Padova], Università degli Studi di Padova = University of Padua (Unipd)-Università degli Studi di Padova = University of Padua (Unipd), Università degli Studi di Trento (UNITN), INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Department of Earth Sciences [Chung-Li City], National Central University [Taiwan] (NCU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), DLR Institute of Planetary Research, German Aerospace Center (DLR), Operations Department (ESAC), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Universita degli Studi di Padova, Consiglio Nazionale delle Ricerche [Roma] (CNR), California Institute of Technology (CALTECH)-NASA, Max-Planck-Institut für Sonnensystemforschung (MPS), European Space Agency (ESA), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Universita degli Studi di Padova-Universita degli Studi di Padova, European Space Agency (ESA)-European Space Agency (ESA), and Universität Bern [Bern]
Subjects: 010504 meteorology & atmospheric sciences, Geometry, Concentric, Classification of discontinuities, 01 natural sciences, Layered structure, 0103 physical sciences, medicine, 010303 astronomy & astrophysics, Comets: individual: 67P/Churyumov, Gerasimenko, 0105 earth and related environmental sciences, Comets: general, Methods: data analysis, Physics, [PHYS]Physics [physics], comets: individual: 67P/Churyumov–Gerasimenko, comets: general, Astronomy and Astrophysics, Dimensional modeling, Ellipsoid, methods: data analysis, Lobe, medicine.anatomical_structure, Space and Planetary Science, Layering, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Free parameter
Abstract: International audience; We provide a three-dimensional model of the inner layered structure of comet 67P based on the hypothesis of an extended layering independently wrapping each lobe. A large set of terrace orientations was collected on the latest shape model and then used as a proxy for the local orientation of the surfaces of discontinuity which defines the layers. We modelled the terraces as a family of concentric ellipsoidal shells with fixed axis ratios, producing a model that is completely defined by just eight free parameters. Each lobe of 67P has been modelled independently, and the two sets of parameters have been estimated by means of non-linear optimization of the measured terrace orientations. The proposed model is able to predict the orientation of terraces, the elongation of cliffs, the linear traces observed in the Wosret and Hathor regions and the peculiar alignment of boulder-like features which has been observed in the Hapi region, which appears to be related to the inner layering of the big lobe. Our analysis allowed us to identify a plane of junction between the two lobes, further confirming the independent nature of the lobes. Our layering models differ from the best-fitting topographic ellipsoids of the surface, demonstrating that the terraces are aligned to an internal structure of discontinuities, which is unevenly exposed on the surface, suggesting a complex history of localized material removal from the nucleus.
Published: 2017
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37. Seasonal Mass Transfer on the Nucleus of Comet 67P/Chuyumov-Gerasimenko

Author: Frank Preusker, Wing-Huen Ip, Laurent Jorda, J. J. López-Moreno, Carsten Güttler, H. Rickman, Michael Küppers, Stubbe F. Hviid, Holger Sierks, Katharina A. Otto, G. Cremonese, M. A. Barucci, J. Deller, Ivano Bertini, Nilda Oklay, P. J. Gutierrez, Michael F. A'Hearn, Marc Hofmann, Nicolas Thomas, Frank Scholten, Jessica Agarwal, P. L. Lamy, Maurizio Pajola, V. Da Deppo, M. De Cecco, J.-R. Kramm, Cecilia Tubiana, Francesco Marzari, Imre Toth, Marco Fulle, Cesare Barbieri, Xian Shi, Stefano Mottola, Yuri V. Skorov, B. J. R. Davidsson, J. L. Bertaux, D. Koschny, Giampiero Naletto, Stefan Schröder, Monica Lazzarin, Dennis Bodewits, Jean-Baptiste Vincent, Sonia Fornasier, H. U. Keller, Jörg Knollenberg, Rafael Rodrigo, Ekkehard Kührt, L. M. Lara, Olivier Groussin, Stefano Debei, DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Department of Physics and Astronomy [Uppsala], Uppsala University, NASA Ames Research Center (ARC), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Universita degli Studi di Padova, Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Centro de Astrobiologia [Madrid] (CAB), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), CNR Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Department of Industrial Engineering [Padova], University of Trento [Trento], Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Operations Department (ESAC), European Space Astronomy Centre (ESAC), European Space Agency (ESA)-European Space Agency (ESA), Department of Information Engineering [Padova] (DEI), Center for Space and Habitability (CSH), University of Bern, Physikalisches Institut [Bern], Universität Bern [Bern], Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Università degli Studi di Padova = University of Padua (Unipd), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Agence Spatiale Européenne = European Space Agency (ESA), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Universität Bern [Bern] (UNIBE), and ITA
Subjects: Asteroiden und Kometen, 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, Comets: individual (67P/Churyumov-Gerasimenko), Methods: data analysis, Comet, Data analysis, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Radiation, Granular material, 01 natural sciences, comet, Mass transfer, individual 67P/Churyumov-Gerasimenko, 0103 physical sciences, medicine, Comets, 010303 astronomy & astrophysics, Southern Hemisphere, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), [PHYS]Physics [physics], [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 520 Astronomy, Planetengeodäsie, Astronomy, Astronomy and Astrophysics, 620 Engineering, medicine.anatomical_structure, 13. Climate action, Space and Planetary Science, Sublimation (phase transition), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Nucleus, Water vapor, Astrophysics - Earth and Planetary Astrophysics
Abstract: We collect observational evidence that supports the scheme of mass transfer on the nucleus of comet 67P/Churyumov-Gerasimenko. The obliquity of the rotation axis of 67P causes strong seasonal variations. During perihelion the southern hemisphere is four times more active than the north. Northern territories are widely covered by granular material that indicates back fall originating from the active south. Decimetre sized chunks contain water ice and their trajectories are influenced by an anti-solar force instigated by sublimation. OSIRIS observations suggest that up to 20 % of the particles directly return to the nucleus surface taking several hours of travel time. The back fall covered northern areas are active if illuminated but produce mainly water vapour. The decimetre chunks from the nucleus surface are too small to contain more volatile compounds such as CO 2 or CO. This causes a north-south dichotomy of the composition measurements in the coma. Active particles are trapped in the gravitational minimum of Hapi during northern winter. They are "shock frozen" and only reactivated when the comet approaches the sun after its aphelion passage. The insolation of the big cavity is enhanced by self-heating, i. e. reflection and IR radiation from the walls. This, together with the pristinity of the active back fall, explains the early observed activity of the Hapi region. Sobek may be a role model for the consolidated bottom of Hapi. Mass transfer in the case of 67P strongly influences the evolution of the nucleus and the interpretation of coma measurements., Comment: 17 pages, 20 figures
Published: 2017
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38. Rosetta Lander - Philae: Operations on comet 67P/Churyumov-Gerasimenko, analysis of wake-up and final state

Author: Sylvain Lodiot, B. Grieger, Jörg Knollenberg, Koen Geurts, Frank Scholten, Laurence O'Rourke, Valentina Lommatsch, Oliver Küchemann, Pablo Muñoz, Stephan Ulamec, Antoine Charpentier, Eric Jurado, Ekkehard Kührt, Stefano Mottola, Rafael Andres, Martin Knapmeyer, Thierry Martin, Cinzia Fantinati, Cedric Delmas, Romain Garmier, Michael Maibaum, and Jens Biele
Subjects: Asteroiden und Kometen, 67P/Churyumov-Gerasimenko, Engineering, 010504 meteorology & atmospheric sciences, Comet, Aerospace Engineering, 01 natural sciences, law.invention, Orbiter, Aeronautics, Planetenphysik, law, 0103 physical sciences, 010303 astronomy & astrophysics, Rosetta Lander, 0105 earth and related environmental sciences, biology, Payload, business.industry, Member states, Planetengeodäsie, biology.organism_classification, Philae, Nutzerzentrum für Weltraumexperimente (MUSC), On board, Osiris, business
Abstract: The Lander Philae, part of the ESA Rosetta mission successfully landed on comet 67P/Churyumov- Gerasimenko on November 12th, 2014. After several (unplanned) bounces it performed a First Scientific Sequence (FSS), based on the energy stored in its on board batteries. All ten instruments of the payload aboard Philae have been operated at least once. Due to the fact that the final landing site was poorly illuminated, Philae went into hibernation on November 15th. Signals from the Lander were received again in June and July 2015, which indicated multiple awakening episodes of the lander. However, various attempts to re-establish reliable and stable communications links failed. Based on the analysis of the data gained during FSS, and during the contacts in June and July 2015 we draw conclusions on the state of Philae. In addition, images from the OSIRIS camera aboard the Rosetta Orbiter have allowed the identification of the exact position of Philae and its attitude, relative to the local surface terrain. This paper also gives an overview of the implications of Philae results for future engineering comet models, required particularly for the design of in-situ (landing) or sample return missions. Rosetta is an ESA mission with contributions from its member states and NASA. Rosetta's Philae Lander is provided by a consortium led by DLR, MPS, CNES and ASI with additional contributions from Hungary, UK, Finland, Ireland and Austria.
Published: 2017

39. The pristine interior of comet 67P revealed by the combined Aswan outburst and cliff collapse

Author: Frank Scholten, Frank Preusker, M. F. A'Hearn, Monica Lazzarin, Ekkehard Kührt, Harald Michalik, Olivier Groussin, Nilda Oklay, Jean-Baptiste Vincent, Luca Penasa, Detlef Koschny, M. De Cecco, Nicolas Thomas, Matteo Massironi, Imre Toth, V. Da Deppo, J. L. Bertaux, Laurent Jorda, Holger Sierks, Björn Davidsson, Carsten Güttler, Emanuele Simioni, Steve Boudreault, Stubbe F. Hviid, S. Höfner, Géza Kovács, Cecilia Tubiana, Sonia Fornasier, Marc Hofmann, Mohamed Ramy El-Maarry, Francesco Marzari, J.-R. Kramm, J. J. Lopez Moreno, Hans Rickman, Maurizio Pajola, Gabriele Cremonese, Giampiero Naletto, Sebastien Besse, M. A. Barucci, Pedro Hasselmann, Michael Küppers, Jörg Knollenberg, Luisa Lara, J. D. P. Deshapriya, Stefano Debei, Francesca Ferri, Rafael Rodrigo, Antoine Pommerol, Jessica Agarwal, H. U. Keller, Cesare Barbieri, Philippe Lamy, Jakob Deller, Zhong-Yi Lin, Stephen C. Lowry, P. J. Gutierrez, Ivano Bertini, W-H. Ip, Clement Feller, Emanuele Baratti, Marco Fulle, Sabrina Ferrari, Alice Lucchetti, Stefano Mottola, NASA Ames Research Center (ARC), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Università degli Studi di Padova = University of Padua (Unipd), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Department of Information Engineering [Padova] (DEI), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), School of Physical Sciences [Canterbury], University of Kent [Canterbury], Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Department of Physics and Astronomy [Uppsala], Uppsala University, Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Operations Department (ESAC), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), Department of Industrial Engineering [Padova], University of Trento [Trento], Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Dipartimento di Geoscienze [Padova], Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), Department of Civil Chemical Environmental and Materials Engineering [Bologna] (DICAM), University of Bologna/Università di Bologna, Universita degli Studi di Padova, Max-Planck-Institut für Sonnensystemforschung (MPS), Consiglio Nazionale delle Ricerche [Roma] (CNR), European Space Agency (ESA), European Space Agency (ESA)-European Space Agency (ESA), Universität Bern [Bern], and University of Bologna
Subjects: outburst, 010504 meteorology & atmospheric sciences, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Escarpment, 01 natural sciences, Aswan, comet, Rosetta, 0103 physical sciences, Cliff, Table (landform), 010303 astronomy & astrophysics, QB, 0105 earth and related environmental sciences, Physics, geography, 67P, geography.geographical_feature_category, biology, cliff, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astronomy, Astronomy and Astrophysics, Crust, Landslide, Albedo, biology.organism_classification, collapse, WAC, 13. Climate action, Osiris, Comet 67/P
Abstract: International audience; Outbursts occur commonly on comets1 with different frequencies and scales2,3. Despite multiple observations suggesting various triggering processes4,5, the driving mechanism of such outbursts is still poorly understood. Landslides have been invoked6 to explain some outbursts on comet 103P/Hartley 2, although the process required a pre-existing dust layer on the verge of failure. The Rosetta mission observed several outbursts from its target comet 67P/Churyumov–Gerasimenko, which were attributed to dust generated by the crumbling of materials from collapsing cliffs7,8. However, none of the aforementioned works included definitive evidence that landslides occur on comets. Amongst the many features observed by Rosetta on the nucleus of the comet, one peculiar fracture, 70 m long and 1 m wide, was identified on images obtained in September 2014 at the edge of a cliff named Aswan9. On 10 July 2015, the Rosetta Navigation Camera captured a large plume of dust that could be traced back to an area encompassing the Aswan escarpment7. Five days later, the OSIRIS camera observed a fresh, sharp and bright edge on the Aswan cliff. Here we report the first unambiguous link between an outburst and a cliff collapse on a comet. We establish a new dust-plume formation mechanism that does not necessarily require the breakup of pressurized crust or the presence of supervolatile material, as suggested by previous studies7. Moreover, the collapse revealed the fresh icy interior of the comet, which is characterized by an albedo >0.4, and provided the opportunity to study how the crumbling wall settled down to form a new talus.The evolution of the collapse of the Aswan cliff9, observed by the OSIRIS Narrow Angle Camera (NAC)10 and the Rosetta Navigation camera (NavCam), is shown in Fig. 1. We estimated a total outburst ejected mass of cometary material between 0.5 × 106 and 1.0 × 106 kg for the 10 July event. By applying stereo-photogrammetric methods11 using multiple OSIRIS images (Supplementary Table 1), we determined the total volume of material that collapsed from the Aswan cliff. In Fig. 2, the dataset that depicts the aspect of the cliff before and after the collapse is presented. By using pre- and post-collapse three-dimensional (3D) models (see Methods), we have been able to measure the dimensions of the collapsed overhang (Supplementary Figs 1–2), deriving a total volume of 2.20 × 104 m3, with a 1σ uncertainty of 0.34 × 104 m3.
Published: 2017
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40. Regional surface morphology of comet 67P/Churyumov-Gerasimenko from Rosetta/OSIRIS images: The southern hemisphere (Corrigendum)

Author: Monica Lazzarin, Laurent Jorda, J. B. Vincent, Cesare Barbieri, N. Thomas, Lorenza Giacomini, Olivier Groussin, S. Fornasier, Simone Marchi, B. J. R. Davidsson, A. Gracia-Berná, Antoine Pommerol, G. Cremonese, A. T. Auger, Raphael Marschall, Detlef Koschny, Matteo Massironi, P. J. Gutierrez, Stubbe F. Hviid, Holger Sierks, Cecilia Tubiana, Michael Küppers, F. Scholten, R. Rodrigo, Maurizio Pajola, N. Oklay, Mohamed Ramy El-Maarry, Ivano Bertini, J. J. Lopez Moreno, Géza Kovács, Hans Rickman, M. A. Barucci, W-H. Ip, J.-R. Kramm, Marco Fulle, P. L. Lamy, M. De Cecco, V. Da Deppo, Sebastien Besse, F. Preusker, Carsten Güttler, Giampiero Naletto, Francesco Marzari, H. U. Keller, M. F. A'Hearn, J. L. Bertaux, J.-C. Lee, Dennis Bodewits, Jörg Knollenberg, E. Kuehrt, L. M. Lara, Stefano Debei, Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), NASA Ames Research Center (ARC), Department of Atmospheric Sciences [Taoyuan City], National Central University [Taiwan] (NCU), Dipartimento di Geoscienze [Padova], Università degli Studi di Padova = University of Padua (Unipd), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Solar System Exploration Research Virtual Institute (SSERVI), Southwest Research Institute [Boulder] (SwRI), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), ESA Scientific Support Office, Agence Spatiale Européenne = European Space Agency (ESA), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Dipartimento di Fisica e Astronomia 'Galileo Galilei', INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Physics and Astronomy [Uppsala], Uppsala University, International Space Science Institute [Bern] (ISSI), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Università degli Studi di Trento (UNITN), Department of Mechanical Engineering [Padova], Department of Industrial Engineering [Padova], Università degli Studi di Padova = University of Padua (Unipd)-Università degli Studi di Padova = University of Padua (Unipd), INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institute of Astronomy [Taiwan] (IANCU), Department of Information Engineering [Padova] (DEI), CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), Universität Bern [Bern], Universita degli Studi di Padova, European Space Agency (ESA), Max-Planck-Institut für Sonnensystemforschung (MPS), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), Consiglio Nazionale delle Ricerche [Roma] (CNR), Universita degli Studi di Padova-Universita degli Studi di Padova, Max Planck Institute for Solar System Research (MPS), and California Institute of Technology (CALTECH)-NASA
Subjects: Asteroiden und Kometen, 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, 530 Physics, Comet, 01 natural sciences, Astrobiology, 0103 physical sciences, Rosetta, comets, OSIRIS, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Physics, biology, 520 Astronomy, Planetengeodäsie, Astronomy, Astronomy and Astrophysics, 500 Science, biology.organism_classification, 620 Engineering, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Osiris, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience
Published: 2017
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41. Constraints on cometary surface evolution derived from a statistical analysis of 67P's topography

Author: E. Kuehrt, Luca Penasa, Giampiero Naletto, Marco Fulle, A. Gicquel, Cesare Barbieri, Francesco Marzari, J. L. Bertaux, Stefano Mottola, Ivano Bertini, F. Preusker, Carsten Güttler, Jakob Deller, Gabriele Cremonese, Zhong-Yi Lin, F. Scholten, Géza Kovács, Hans Rickman, Steve Boudreault, Monica Lazzarin, Jörg Knollenberg, L. M. Lara, V. Da Deppo, M. A. Barucci, Michael Küppers, Holger Sierks, Stubbe F. Hviid, Detlef Koschny, J. J. Lopez Moreno, M. De Cecco, P. Gutiérrez-Marquez, Nicolas Thomas, Björn Davidsson, Cecilia Tubiana, Xian Shi, Imre Toth, N. Oklay, Philippe Lamy, Stefano Debei, Maurizio Pajola, X. Hu, Wing-Huen Ip, J. B. Vincent, J.-R. Kramm, Laurent Jorda, Sonia Fornasier, D. de Niem, Marc Hofmann, P. J. Gutierrez, Clement Feller, R. Rodrigo, M. F. A'Hearn, Olivier Groussin, Horst Uwe Keller, DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), NASA Ames Research Center (ARC), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Universita degli Studi di Padova, Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Department of Physics and Astronomy [Uppsala], Uppsala University, Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Padova (OAPD), CNR Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Department of Industrial Engineering [Padova], University of Trento [Trento], Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Department of Information Engineering [Padova] (DEI), Operations Department (ESAC), European Space Astronomy Centre (ESAC), European Space Agency (ESA)-European Space Agency (ESA), Dipartimento di Geoscienze [Padova], Center for Space and Habitability (CSH), University of Bern, Physikalisches Institut [Bern], Universität Bern [Bern], Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), NASA-California Institute of Technology (CALTECH), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), Università degli Studi di Padova = University of Padua (Unipd), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Agence Spatiale Européenne = European Space Agency (ESA), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), and Universität Bern [Bern] (UNIBE)
Subjects: Surface (mathematics), 010504 meteorology & atmospheric sciences, Distribution (number theory), Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, 01 natural sciences, comet, surface evolution, topography, statistical analysis, Rosetta, 0103 physical sciences, Statistical analysis, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, [PHYS]Physics [physics], 67P, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 520 Astronomy, Comets: individual: 67P, Astronomy and Astrophysics, Geophysics, Comets: general, 620 Engineering, 13. Climate action, Space and Planetary Science, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract: We present a statistical analysis of the distribution of large-scale topographic features on comet 67P/Churyumov-Gerasimenko.We observe that the cumulative cliff height distribution across the surface follows a power law with a slope equal to -1.69 ± 0.02. When this distribution is studied independently for each region, we find a good correlation between the slope of the power law and the orbital erosion rate of the surface. For instance, the Northern hemisphere topography is dominated by structures on the 100 m scale, while the Southern hemisphere topography, illuminated at perihelion, is dominated by 10 m scale terrain features. Our study suggests that the current size of a cliff is controlled not only by material cohesion but also by the dominant erosional process in each region. This observation can be generalized to other comets, where we argue that primitive nuclei are characterized by the presence of large cliffs with a cumulative height-power index equal to or above -1.5, while older, eroded cometary surfaces have a power index equal to or below -2.3. In effect, our model shows that a measure of the topography provides a quantitative assessment of a comet's erosional history, that is, its evolutionary age. © 2017 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.
Published: 2017
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42. Post-perihelion photometry of dust grains in the coma of 67P Churyumov-Gerasimenko

Author: Carsten Güttler, Xian Shi, Ekkehard Kührt, L. M. Lara, Alice Lucchetti, Cesare Barbieri, J. B. Vincent, Stefano Mottola, P. Lamy, Hans Rickman, P. J. Gutierrez, Theresa Ott, Jakob Deller, Matteo Massironi, Jörg Knollenberg, Luca Penasa, Stubbe F. Hviid, Holger Sierks, Michael Küppers, F. La Forgia, J.-R. Kramm, J. L. Bertaux, Nilda Oklay, Ivano Bertini, Gabriele Cremonese, Wing-Huen Ip, Laurent Jorda, M. A. Barucci, Monica Lazzarin, J. J. Lopez Moreno, M. F. A'Hearn, Stefano Debei, Olivier Groussin, E. Frattin, V. Da Deppo, Emanuele Simioni, B. J. R. Davidsson, Horst Uwe Keller, Marc Hofmann, R. Rodrigo, Maurizio Pajola, A. Gicquel, Cecilia Tubiana, Sonia Fornasier, M. De Cecco, Giampiero Naletto, Francesco Marzari, Francesca Ferri, Jessica Agarwal, Marco Fulle, Detlef Koschny, Esther Drolshagen, Sabrina Ferrari, Nicolas Thomas, ITA, USA, GBR, FRA, DEU, INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Università degli Studi di Padova = University of Padua (Unipd), CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), University of Oldenburg, Carl Von Ossietzky Universität Oldenburg = Carl von Ossietzky University of Oldenburg (OFFIS), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), International Space Science Institute [Bern] (ISSI), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Physics and Astronomy [Uppsala], Uppsala University, Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Industrial Engineering [Padova], University of Trento [Trento], Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), European Space Astronomy Centre (ESAC), Dipartimento di Geoscienze [Padova], Department of Information Engineering [Padova] (DEI), NASA Ames Research Center (ARC), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Universita degli Studi di Padova, Consiglio Nazionale delle Ricerche [Roma] (CNR), Carl Von Ossietzky Universität Oldenburg, Max-Planck-Institut für Sonnensystemforschung (MPS), European Space Agency (ESA), Universität Bern [Bern], Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), and Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA)
Subjects: Asteroiden und Kometen, 010504 meteorology & atmospheric sciences, Comet, Data analysis, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astrophysics, 01 natural sciences, Spectral line, Photometry (optics), Photometry, Methods: data analysis, 0103 physical sciences, Spectral slope, Rosetta, Comets, OSIRIS, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, [PHYS]Physics [physics], [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 520 Astronomy, Zodiacal dust, Astronomy and Astrophysics, 620 Engineering, Comets: general, Wavelength, Techniques: photometric, Space and Planetary Science, Water ice, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Automated method
Abstract: International audience; We present a photometric analysis of individual dust grains in the coma of comet 67P/Churyumov–Gerasimenko using OSIRIS images taken from 2015 July to 2016 January. We analysed a sample of 555 taken during 18 d at heliocentric distances ranging between 1.25 and 2.04 au and at nucleocentric distances between 80 and 437 km. An automated method to detect the tracks was specifically developed. The images were taken by OSIRIS NAC in four different filters: Near-IR (882 nm), Orange (649 nm), FarOrange (649 nm) and Blue (480 nm). It was not always possible to recognize all the grains in the four filters, hence we measured the spectral slope in two wavelengths ranges: in the interval [480–649] nm, for 1179 grains, and in the interval [649–882] nm, for 746 grains. We studied the evolution of the two populations’ average spectral slopes. The data result scattered around the average value in the range [480–649] nm, while in the [649–882] nm we observe a slight decreasing moving away from the Sun as well as a slight increasing with the nucleocentric distance. A spectrophotometric analysis was performed on a subsample of 339 grains. Three major groups were defined, based on the spectral slope between [535–882] nm: (i) the steep spectra that may be related with organic material, (ii) the spectra with an intermediate slope, likely a mixture of silicates and organics and (iii) flat spectra that may be associated with a high abundance of water ice.
Published: 2017
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43. Geomorphological and spectrophotometric analysis of Seth's circular niches on comet 67P/Churyumov–Gerasimenko using OSIRIS images

Author: Monica Lazzarin, M. F. A'Hearn, Björn Davidsson, Cecilia Tubiana, Marco Fulle, Olivier Groussin, Frank Scholten, J.-B. Vincent, Sabrina Ferrari, Ekkehard Kührt, Xian Shi, Horst Uwe Keller, Stefano Mottola, L. M. Lara, Ivano Bertini, Michael Küppers, P. J. Gutierrez, Steve Boudreault, R. Rodrigo, Alice Lucchetti, Carsten Güttler, L. Z. Lin, F. La Forgia, Cesare Barbieri, Nilda Oklay, Jakob Deller, Holger Sierks, Sonia Fornasier, Detlef Koschny, Nicolas Thomas, V. Da Deppo, Maurizio Pajola, Clement Feller, Wing-Huen Ip, Laurent Jorda, M. Hoffman, Giampiero Naletto, Pedro Hasselmann, Jörg Knollenberg, J.-R. Kramm, Luca Penasa, G. Cremonese, Stefano Debei, M. De Cecco, J. L. Bertaux, J. J. Lopez Moreno, Philippe Lamy, M. A. Barucci, Matteo Massironi, Stubbe F. Hviid, Jessica Agarwal, Francesco Marzari, Hans Rickman, Frank Preusker, INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), NASA Ames Research Center (ARC), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Università degli Studi di Padova = University of Padua (Unipd), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Dipartimento di Geoscienze [Padova], CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Department of Information Engineering [Padova] (DEI), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Dipartimento di Fisica e Astronomia 'Galileo Galilei', International Space Science Institute [Bern] (ISSI), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Physics and Astronomy [Uppsala], Uppsala University, Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Department of Industrial Engineering [Padova], University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), European Space Astronomy Centre (ESAC), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Universita degli Studi di Padova, Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Consiglio Nazionale delle Ricerche [Roma] (CNR), Max-Planck-Institut für Sonnensystemforschung (MPS), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), European Space Agency (ESA), Universität Bern [Bern], and California Institute of Technology (CALTECH)-NASA
Subjects: 010504 meteorology & atmospheric sciences, comets: general-comets, Comet, Data analysis, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Terrain, 67P/Churyumov–Gerasimenko, 01 natural sciences, individual: 67P/Churyumov-Gerasimenko-methods:data analysis, Methods: data analysis, 0103 physical sciences, Size frequency, Cliff, 010303 astronomy & astrophysics, Geomorphology, 0105 earth and related environmental sciences, Remote sensing, Comets: individual: 67P/Churyumov, Gerasimenko, Physics, Ecological niche, Comets: general, geography, geography.geographical_feature_category, biology, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 520 Astronomy, Astronomy and Astrophysics, Landslide, biology.organism_classification, 620 Engineering, 13. Climate action, Space and Planetary Science, Water ice, Osiris
Abstract: International audience; We provide a detailed geomorphological and spectrophotometric analysis of the circular niches located on the Seth region of 67P using OSIRIS images. The features can be related to landslide events that occurred on 67P and shaped its surface, as the recent Aswan cliff collapse detected in the same region. We therefore provide an analysis of the area pre- and post-perihelion suggesting that no specific changes have been observed. To assess this, after performing a geomorphological map of the area that allows us to identify different terrain units, we computed the boulders cumulative size frequency distribution (SFD) of the niches, before and after the perihelion passage. The niches SFDs are characterized by a similar trend with two different power-law indices within the same deposit: lower power-law value (between −2.3 and −2.7) for boulders smaller than 5 m and steeper power-law value (between −4.7 and −5.0) for boulders larger than 5 m. These trends suggest that smaller boulders have evolved and progressively have been depleted (lower power-law index), while bigger boulders are more representative of the event that generated the deposit and are less degraded. Then, we perform the spectrophotometric analysis of this region comparing pre- and post-perihelion results. We found colour changes within the area, in particular brighter patches related to the presence of exposed water ice mixed to the refractory materials have been detected in the post-perihelion images.
Published: 2017
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44. Cliffs versus Plains: Can ROSINA/COPS and OSIRIS data of comet 67P/Churyumov-Gerasimenko in autumn 2014 constrain inhomogeneous outgassing?

Author: Stefano Mottola, Yuri V. Skorov, Raphael Marschall, Frank Scholten, Jörg Knollenberg, Ekkehard Kührt, Nicolas Thomas, Martin Rubin, I. L. Lai, H. Sierks, Jong-Shinn Wu, Frank Preusker, Ying Liao, C. C. Su, Kathrin Altwegg, Wing-Huen Ip, Laurent Jorda, J.-B. Vincent, H. U. Keller, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES)
Subjects: Brightness, 010504 meteorology & atmospheric sciences, data Analysis, Mie scattering, Astrophysics, 01 natural sciences, law.invention, rosetta, modelling, Orbiter, law, 0103 physical sciences, comets, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Spectrometer, biology, Astronomy, Astronomy and Astrophysics, biology.organism_classification, Outgassing, [SDU]Sciences of the Universe [physics], 13. Climate action, Space and Planetary Science, Sublimation (phase transition), Direct simulation Monte Carlo, Osiris
Abstract: International audience; Context. This paper describes the modelling of gas and dust data acquired in the period August to October 2014 from the European Space Agency's Rosetta spacecraft when it was in close proximity to the nucleus of comet 67P/Churyumov‐Gerasimenko. Aims. With our 3D gas and dust comae models this work attempts to test the hypothesis that cliff activity on comet 67P/Churyumov‐Gerasimenko can solely account for the local gas density data observed by the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) and the dust brightnesses seen by the Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) in the considered time span. Methods. The model uses a previously developed shape model of the nucleus. From this, the water sublimation rates and gas temperatures at the surface are computed. The gas expansion is modelled with a 3D Direct Simulation Monte Carlo algorithm. A dust drag algorithm is then used to compute dust volume number densities in the coma, which are then converted to brightnesses using Mie theory and a line‐of‐sight integration. Furthermore we have studied the impact of topographic re‐radiation on the models. Results. We show that gas activity from only cliff areas produces a fit to the ROSINA/COPS data that is as statistically good as a purely insolation‐driven model. In contrast, pure cliff activity does not reproduce the dust brightness observed by OSIRIS and can thus be ruled out. On the other hand, gas activity from the Hapi region in addition to cliff activity produces a statistically better fit to the ROSINA/COPS data than purely insolation‐driven outgassing and also fits the OSIRIS observations rather well. We found that topographic re‐radiation does not contribute significantly to the sublimation behaviour of H2O but plays an important role in how the gas flux interacts with the irregular shape of the nucleus. Conclusions. We demonstrate that fits to the observations are non‐unique. We can conclude however that gas and dust activity from cliffs and the Hapi region are consistent with the ROSINA/COPS and OSIRIS data sets for the considered time span and are thus a plausible solution. Models with activity from low gravitational slopes alone provide a statistically inferior solution.
Published: 2017
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45. Investigating the physical properties of outbursts on comet 67P/Churyumov-Gerasimenko

Author: I. L. Lai, W-H. Ip, Xian Shi, Holger Sierks, Stefano Mottola, Ivano Bertini, Laurent Jorda, Dennis Bodewits, Michael Küppers, Detlef Koschny, Marc Hofmann, M. A. Barucci, J. L. Bertaux, P. J. Gutierrez, Carsten Güttler, M. De Cecco, Nilda Oklay, R. Rodrigo, Jessica Agarwal, Giampiero Naletto, B. J. R. Davidsson, Esther Drolshagen, V. Da Deppo, N. Thomas, Cesare Barbieri, Philippe Lamy, Géza Kovács, Theresa Ott, Jakob Deller, Stubbe F. Hviid, Marco Fulle, Zhong-Yi Lin, J.-R. Kramm, Hans Rickman, Cecilia Tubiana, J-C. Lee, Monica Lazzarin, J. J. López-Moreno, Jean-Baptiste Vincent, Francesco Marzari, Jörg Knollenberg, Sonia Fornasier, M. F. A'Hearn, Olivier Groussin, Horst Uwe Keller, Ekkehard Kührt, L. M. Lara, Stefano Debei, Gabriele Cremonese, Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Institute of Space Science [Taiwan], Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Department of Physics and Astronomy [Uppsala], Uppsala University, Department of Industrial Engineering [Padova], University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Department of Earth Sciences [Chung-Li City], Department of Information Engineering [Padova] (DEI), University of Oldenburg, Physikalisches Institut [Bern], Universität Bern [Bern], Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), Polska Akademia Nauk (PAN), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), IMPEC - LATMOS, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Università degli Studi di Padova = University of Padua (Unipd), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Universität Bern [Bern] (UNIBE), ITA, USA, GBR, FRA, and DEU
Subjects: 010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, Comet, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Astrobiology, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, Comets: individual: 67P/Churyumov-Gerasimenko, comets: individual: 67P/Churyumov–Gerasimenko, Astronomy and Astrophysics, Space and Planetary Science, Spacecraft, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], business.industry, Astrophysics::Instrumentation and Methods for Astrophysics, [PHYS.PHYS.PHYS-SPACE-PH]Physics [physics]/Physics [physics]/Space Physics [physics.space-ph], 13. Climate action, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, business
Abstract: Cometary outbursts on several comets have been observed both by ground-based telescopes and by in situ instruments on spacecraft. However, the mechanism behind these phenomena and their physical properties are still unclear. The optical, spectrocopic and infrared remote imaging system (OSIRIS) onboard the Rosetta spacecraft provided first-hand information on the outbursts from comet 67P/Churyumov-Gerasimenko during its perihelion passage in 2015. The physical properties of the outbursts can be investigated by examining the time series of these high-resolution images. An analysis is made of the wide- and narrow-angle images obtained during the monitoring of the outburst sequences, which occurred between July and September in 2015. A ring-masking technique is used to calculate the excess brightness of the outbursts. The ejected mass and expansion velocity of the outbursts is estimated from differences in images made with the same filter (orange filter). The calculated excess brightness from these outburst plumes ranges from a few per cent to 28 per cent. In some major outbursts, the brightness contribution from the outburst plume can be one or two times higher than that of the typical coma jet activities. The strongest event was the perihelion outburst detected just a few hours before perihelion. The mass ejection rate during a generic outburst could reach a few per cent of the steady-state value of the dust coma. Transient events are detected by studying the brightness slope of the outburst plume with continuous streams of outflowing gas and dust triggered by driving mechanisms, as yet not understood, which remain active for several minutes to less than a few hours.
Published: 2017
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46. Characterization of dust aggregates in the vicinity of the Rosetta spacecraft

Author: Wing-Huen Ip, Carsten Güttler, Marco Fulle, Detlef Koschny, Nicolas Thomas, Laurent Jorda, Yuan Li, Nilda Oklay, H. U. Keller, J.-R. Kramm, J.-B. Vincent, Pedro Hasselmann, Cesare Barbieri, P. Gutiérrez Marqués, V. Da Deppo, Marc Hofmann, Sonia Fornasier, Ivano Bertini, Jakob Deller, Holger Sierks, P. J. Gutierrez, M. De Cecco, J. L. Bertaux, Michael Küppers, M. F. A'Hearn, Francesco Marzari, Olivier Groussin, Jörg Knollenberg, Björn Davidsson, Maurizio Pajola, J. J. López-Moreno, Jessica Agarwal, R. Rodrigo, Cecilia Tubiana, Theresa Ott, Bernhard Geiger, Stubbe F. Hviid, Géza Kovács, Monica Lazzarin, Giampiero Naletto, M. A. Barucci, Steve Boudreault, Dennis Bodewits, Esther Drolshagen, Xian Shi, Stefano Mottola, Ekkehard Kührt, L. M. Lara, Hans Rickman, Stefano Debei, Gabriele Cremonese, Philippe Lamy, Swedish National Space Board, Ministerio de Economía y Competitividad (España), German Centre for Air and Space Travel, Agenzia Spaziale Italiana, Centre National de la Recherche Scientifique (France), European Space Agency, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), University of Oldenburg, Carl Von Ossietzky Universität Oldenburg = Carl von Ossietzky University of Oldenburg (OFFIS), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Università degli Studi di Padova = University of Padua (Unipd), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Department of Physics and Astronomy [Uppsala], Uppsala University, Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Padova (OAPD), CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Department of Industrial Engineering [Padova], University of Trento [Trento], Operations Department (ESAC), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], NASA Ames Research Center (ARC), Center for Space and Habitability (CSH), University of Bern, Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Max-Planck-Institut für Sonnensystemforschung (MPS), Carl Von Ossietzky Universität Oldenburg, Universita degli Studi di Padova, European Space Agency (ESA), Consiglio Nazionale delle Ricerche [Roma] (CNR), California Institute of Technology (CALTECH)-NASA, European Space Agency (ESA)-European Space Agency (ESA), Universität Bern [Bern], Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), and Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA)
Subjects: Asteroiden und Kometen, 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Techniques: image processing, Image processing, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Comets: general, Comets: individual: 67P/ Churyumov-Gerasimenko, Astrobiology, Physics::Plasma Physics, individual: 67P/Churyumov-Gerasimenko [Comets], 0103 physical sciences, Rosetta, Comets, image processing [Techniques], OSIRIS, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Dynamic motion, Physics, [PHYS]Physics [physics], Comets: individual: 67P/Churyumov-Gerasimenko, biology, Spacecraft, business.industry, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 520 Astronomy, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, general [Comets], Astronomy and Astrophysics, biology.organism_classification, 620 Engineering, Characterization (materials science), Space and Planetary Science, Physics::Space Physics, Particle, Astrophysics::Earth and Planetary Astrophysics, Osiris, business, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: In a Rosetta/OSIRIS imaging activity in 2015 June, we have observed the dynamic motion of particles close to the spacecraft. Due to the focal setting of the OSIRIS wide angle camera, these particles were blurred, which can be used to measure their distances to the spacecraft. We detected 109 dust aggregates over a 130 min long sequence, and find that their sizes are around a millimetre and their distances cluster between 2 and 40 m from the spacecraft. Their number densities are about a factor 10 higher than expected for the overall coma and highly fluctuating. Their velocities are small compared to the spacecraft orbital motion and directed away from the spacecraft, towards the comet. From this we conclude that they have interacted with the spacecraft and assess three possible scenarios. In the likeliest of the three scenarios, centimetre-sized aggregates collide with the spacecraft and we would observe the fragments. Ablation of a dust layer on the spacecraft's z panel (remote instrument viewing direction) when rotated towards the Sun is a reasonable alternative. We could also measure an acceleration for a subset of 18 aggregates, which is directed away from the Sun and can be explain by a rocket effect, which requires a minimum ice fraction of the order of 0.1 per cent.© 2017 The Authors., The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB) and the ESA Technical Directorate is gratefully acknowledged.
Published: 2017
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47. The highly active Anhur–Bes regions in the 67P/Churyumov–Gerasimenko comet: results from OSIRIS/ROSETTA observations

Author: Pedro Hasselmann, Philippe Lamy, Clement Feller, J. L. Bertaux, Xian Shi, M. F. A'Hearn, Olivier Groussin, M. De Cecco, Maurizio Pajola, M. L. Lara, J.-C. Lee, J.-B. Vincent, Holger Sierks, Stefano Mottola, Nilda Oklay, Marco Fulle, Wing-Huen Ip, Laurent Jorda, Cesare Barbieri, Imre Toth, Lorenza Giacomini, M. A. Barucci, Carsten Güttler, Jakob Deller, Sabrina Ferrari, V. Da Deppo, J. J. Lopez Moreno, Zhong-Yi Lin, Marc Hofmann, Sonia Fornasier, Detlef Koschny, Ivano Bertini, H. U. Keller, Nicolas Thomas, Michael Küppers, Jörg Knollenberg, Jessica Agarwal, Rafael Rodrigo, Giampiero Naletto, J. D. P. Deshapriya, Stefano Debei, Ekkehard Kührt, Géza Kovács, Gabriele Cremonese, Monica Lazzarin, Francesco Marzari, P. J. Gutiérrez, R. Kramm, Björn Davidsson, Matteo Massironi, Cecilia Tubiana, Stubbe F. Hviid, Mohamed Ramy El-Maarry, Hans Rickman, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Department of Atmospheric Sciences [Taoyuan City], National Central University [Taiwan] (NCU), Dipartimento di Geoscienze [Padova], Università degli Studi di Padova = University of Padua (Unipd), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institute of Astronomy [Taiwan] (IANCU), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Dipartimento di Fisica e Astronomia 'Galileo Galilei', Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Department of Physics and Astronomy [Uppsala], Uppsala University, Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Department of Industrial Engineering [Padova], University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Universita degli Studi di Padova, Max-Planck-Institut für Sonnensystemforschung (MPS), European Space Agency (ESA), Consiglio Nazionale delle Ricerche [Roma] (CNR), California Institute of Technology (CALTECH)-NASA, Universität Bern [Bern], Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), and Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA)
Subjects: comets: individual: 67P/Churyumov-Gerasimenko, Methods: data analysis, Methods: observational, Techniques: photometric, 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, Outcrop, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Astrophysics, Fault scarp, 01 natural sciences, Mantle (geology), 0103 physical sciences, Spectral slope, OSIRIS, 010303 astronomy & astrophysics, Southern Hemisphere, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), [PHYS]Physics [physics], biology, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 520 Astronomy, Astronomy, Astronomy and Astrophysics, biology.organism_classification, 620 Engineering, Plume, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], 13. Climate action, Space and Planetary Science, Layering, Osiris, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract: The Southern hemisphere of the 67P/Churyumov-Gerasimenko comet has become visible from Rosetta only since March 2015. It was illuminated during the perihelion passage and therefore it contains the regions that experienced the strongest heating and erosion rate, thus exposing the subsurface most pristine material. In this work we investigate, thanks to the OSIRIS images, the geomorphology, the spectrophotometry and some transient events of two Southern hemisphere regions: Anhur and part of Bes. Bes is dominated by outcropping consolidated terrain covered with fine particle deposits, while Anhur appears strongly eroded with elongated canyon-like structures, scarp retreats, different kinds of deposits, and degraded sequences of strata indicating a pervasive layering. We discovered a new 140 m long and 10 m high scarp formed in the Anhur/Bes boundary during/after the perihelion passage, close to the area where exposed CO$_2$ and H$_2$O ices were previously detected. Several jets have been observed originating from these regions, including the strong perihelion outburst, an active pit, and a faint optically thick dust plume. We identify several areas with a relatively bluer slope (i.e. a lower spectral slope value) than their surroundings, indicating a surface composition enriched with some water ice. These spectrally bluer areas are observed especially in talus and gravitational accumulation deposits where freshly exposed material had fallen from nearby scarps and cliffs. The investigated regions become spectrally redder beyond 2 au outbound when the dust mantle became thicker, masking the underlying ice-rich layers., 16 pages, 15 figures, published online on 24 May 2017 on Mon. Not. R. Astron. Soc. stx1275, https://doi.org/10.1093/mnras/stx1275
Published: 2017
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48. Thermal modelling of water activity on comet 67P/Churyumov-Gerasimenko with global dust mantle and plural dust-to-ice ratio

Author: J.-R. Kramm, J.-B. Vincent, Michael Küppers, X. Hu, Gabriele Cremonese, J. J. López-Moreno, J. Agarwal, Marco Fulle, I. Hall, Maria Antonieta Barucci, M. F. A'Hearn, Björn Davidsson, Stefano Debei, Olivier Groussin, Ivano Bertini, J. Ripken, Maurizio Pajola, Ekkehard Kührt, Stubbe F. Hviid, Cecilia Tubiana, L. M. Lara, J. L. Bertaux, Giampiero Naletto, I. Büttner, Cesare Barbieri, Sonia Fornasier, Xian Shi, Nilda Oklay, R. Rodrigo, Juergen Oberst, Jakob Deller, Stefano Mottola, P. Gutierrez-Marques, C. Güttler, Detlef Koschny, Francesco Marzari, V. Da Deppo, Nicolas Thomas, P. J. Gutierrez, Jürgen Blum, Monica Lazzarin, Hans Rickman, Géza Kovács, H. U. Keller, Holger Sierks, Jörg Knollenberg, M. L. Richards, Wing-Huen Ip, Philippe Lamy, Laurent Jorda, Marc Hofmann, Steve Boudreault, M. De Cecco, Bastian Gundlach, Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Technische Universität Berlin (TU), Institut für Geodäsie und Geoinformationstechnik, Moscow State University of Geodesy and Cartography (MIIGAiK), INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), NASA Ames Research Center (ARC), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), International Space Science Institute [Bern] (ISSI), Centro de Astrobiologia [Madrid] (CAB), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Physics and Astronomy [Uppsala], Uppsala University, Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Padova (OAPD), CNR Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Department of Industrial Engineering [Padova], University of Trento [Trento], Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), DLR Institute of Planetary Research, German Aerospace Center (DLR), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Operations Department (ESAC), European Space Astronomy Centre (ESAC), European Space Agency (ESA)-European Space Agency (ESA), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Department of Information Engineering [Padova] (DEI), Physikalisches Institut [Bern], Universität Bern [Bern], Center for Space and Habitability (CSH), University of Bern, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Technical University of Berlin / Technische Universität Berlin (TU), Università degli Studi di Padova = University of Padua (Unipd), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Agence Spatiale Européenne = European Space Agency (ESA), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Universität Bern [Bern] (UNIBE), and California Institute of Technology (CALTECH)-NASA
Subjects: Solid state: refractory, Asteroiden und Kometen, 67P/Churyumov-Gerasimenko, Insolation, 010504 meteorology & atmospheric sciences, Water activity, Comet, Volatile, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], 01 natural sciences, Mantle (geology), Solid state: volatile -methods: numerical, Astrobiology, 0103 physical sciences, Thermal, Comets, medicine, Comets: individual (67P/Churyumov-Gerasimenko), 010303 astronomy & astrophysics, Comets: general, 0105 earth and related environmental sciences, [PHYS]Physics [physics], Physics, Refractory, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 520 Astronomy, Planetengeodäsie, Astronomy and Astrophysics, Geophysics, 620 Engineering, medicine.anatomical_structure, Space and Planetary Science, Sublimation (phase transition), Numerical methods, Water ice, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Nucleus
Abstract: International audience; We perform a thermo-physical analysis on water activity of comet 67P/Churyumov-Gerasimenko (67P). The sublimation of water is assumed to occur from beneath a global, desiccated dust mantle over the irregular-shaped nucleus. The concept of two thermal models, the recipe of model formulation and the strategy of application to comet 67P are described. For an accurate and efficient evaluation of energy input by insolation and self-heating over the nucleus, a Landscape data base is devised based on polyhedral shape models of the nucleus. We apply the thermal models to investigate the impact of certain parameters of nucleus properties on water production. It is found that the measured water production of 67P can be overall attributed to sublimation of water ice with a mass abundance of a few to 10 per cent beneath a uniform dust mantle of several millimetres to one centimetre in thickness. Insofar as 67P is concerned, we argue against the necessity to invoke assumptions on localized water activity, or on the distinction of active/dormant surface areas.
Published: 2017
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49. Dust mass distribution around comet 67P/Churyumov–Gerasimenko determined via parallax measurements using Rosetta's OSIRIS cameras

Author: J.-R. Kramm, P. J. Gutiérrez, M. F. A'Hearn, Olivier Groussin, J.-B. Vincent, Cesare Barbieri, E. Frattin, J. J. López-Moreno, Björn Poppe, Jakob Deller, M. De Cecco, Detlef Koschny, Nilda Oklay, Giampiero Naletto, Maurizio Pajola, Steve Boudreault, Zhong-Yi Lin, Clement Feller, V. Da Deppo, Marco Fulle, J. L. Bertaux, Géza Kovács, P. I. Lamy, Carsten Güttler, Wing-Huen Ip, Laurent Jorda, Francesco Marzari, E. Drolshagen, Stubbe F. Hviid, M. A. Barucci, Ivano Bertini, Marc Hofmann, Hans Rickman, Holger Sierks, Björn Davidsson, Jörg Knollenberg, Cecilia Tubiana, Monica Lazzarin, H. U. Keller, Jessica Agarwal, Bernhard Geiger, Michael Küppers, Sonia Fornasier, Xian Shi, T. Ott, Stefano Mottola, R. Rodrigo, A. Gicquel, Nicolas Thomas, Gabriele Cremonese, Ekkehard Kührt, L. M. Lara, Stefano Debei, University of Oldenburg, Carl Von Ossietzky Universität Oldenburg, Technische Universität Munchen - Université Technique de Munich [Munich, Allemagne] (TUM), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), International Space Science Institute [Bern] (ISSI), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Physics and Astronomy [Uppsala], Uppsala University, Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), CNR Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Department of Industrial Engineering [Padova], University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), Operations Department (ESAC), European Space Astronomy Centre (ESAC), European Space Agency (ESA)-European Space Agency (ESA), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Department of Information Engineering [Padova] (DEI), NASA Ames Research Center (ARC), Physikalisches Institut [Bern], Universität Bern [Bern], Carl Von Ossietzky Universität Oldenburg = Carl von Ossietzky University of Oldenburg (OFFIS), Agence Spatiale Européenne = European Space Agency (ESA), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Università degli Studi di Padova = University of Padua (Unipd), NASA-California Institute of Technology (CALTECH), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Universität Bern [Bern] (UNIBE), ITA, USA, GBR, FRA, DEU, German Centre for Air and Space Travel, Agenzia Spaziale Italiana, Ministerio de Economía y Competitividad (España), Swedish National Space Board, European Space Agency, Centre National de la Recherche Scientifique (France), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)
Subjects: Asteroiden und Kometen, 010504 meteorology & atmospheric sciences, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Techniques: image processing, Coma (optics), 01 natural sciences, individual: 67P/Churyumov-Gerasimenko [Comets], Rosetta, 0103 physical sciences, Spectral slope, image processing [Techniques], OSIRIS, 010303 astronomy & astrophysics, Comets: general, Comets: individual: 67P/Churyumov-Gerasimenko, Parallaxes, 0105 earth and related environmental sciences, Physics, [PHYS]Physics [physics], Range (particle radiation), Mass distribution, Spacecraft, business.industry, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 520 Astronomy, general [Comets], Astronomy, Astronomy and Astrophysics, 620 Engineering, Space and Planetary Science, Particle, Parallax, business, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: The OSIRIS (optical, spectroscopic and infrared remote imaging system) instrument on board the ESA Rosetta spacecraft collected data of 67P/Churyumov-Gerasimenko for over 2 yr. OSIRIS consists of two cameras, a Narrow Angle Camera and a Wide Angle Camera. For specific imaging sequences related to the observation of dust aggregates in 67P's coma, the two cameras were operating simultaneously. The two cameras are mounted 0.7 m apart from each other, as a result this baseline yields a parallax shift of the apparent particle trails on the analysed images directly proportional to their distance. Thanks to such shifts, the distance between observed dust aggregates and the spacecraft was determined. This method works for particles closer than 6000 m to the spacecraft and requires very few assumptions. We found over 250 particles in a suitable distance range with sizes of some centimetres, masses in the range of 10-10 kg and a mean velocity of about 2.4 m s relative to the nucleus. Furthermore, the spectral slope was analysed showing a decrease in the median spectral slope of the particles with time. The further a particle is from the spacecraft the fainter is its signal. For this reason, this was counterbalanced by a debiasing. Moreover, the dust mass-loss rate of the nucleus could be computed as well as the Af ρ of the comet around perihelion. The summed-up dust mass-loss rate for the mass bins 10-10 kg is almost 8300 kg s.© 2017 The Authors., The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB) and the ESA Technical Directorate is gratefully acknowledged.
Published: 2017
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50. Distance determination method of dust particles using Rosetta OSIRIS NAC and WAC data

Author: Ivano Bertini, Björn Poppe, Marco Fulle, Nilda Oklay, V. Da Deppo, M. De Cecco, Monica Lazzarin, J. J. Lopez Moreno, Wing-Huen Ip, Laurent Jorda, Clement Feller, J.-R. Kramm, Theresa Ott, P. Lamy, P. J. Gutierrez, R. Rodrigo, Esther Drolshagen, A. Gicquel, Detlef Koschny, Marc Hofmann, Xian Shi, Jessica Agarwal, M. F. A'Hearn, Olivier Groussin, Stubbe F. Hviid, Francesco Marzari, Cesare Barbieri, Gabriele Cremonese, J. L. Bertaux, Jakob Deller, Ekkehard Kührt, Hans Rickman, L. M. Lara, Carsten Güttler, Björn Davidsson, Cecilia Tubiana, H. U. Keller, Stefano Debei, Holger Sierks, M. A. Barucci, Giampiero Naletto, Jörg Knollenberg, Sonia Fornasier, Michael Küppers, Nicolas Thomas, Carl Von Ossietzky Universität Oldenburg, European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Technische Universität Munchen - Université Technique de Munich [Munich, Allemagne] (TUM), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), Department of Physics and Astronomy [Uppsala], Uppsala University, Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Akademie der Wissenschaften zu Göttingen, Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Department of Industrial Engineering [Padova], INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), DLR Institute of Planetary Research, German Aerospace Center (DLR), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Operations Department (ESAC), European Space Astronomy Centre (ESAC), European Space Agency (ESA)-European Space Agency (ESA), Department of Information Engineering [Padova] (DEI), Physikalisches Institut [Bern], Universität Bern [Bern], Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Carl Von Ossietzky Universität Oldenburg = Carl von Ossietzky University of Oldenburg (OFFIS), Agence Spatiale Européenne = European Space Agency (ESA), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Università degli Studi di Padova = University of Padua (Unipd), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Universität Bern [Bern] (UNIBE), ITA, USA, GBR, FRA, and DEU
Subjects: Asteroiden und Kometen, 67P/Churyumov-Gerasimenko, Offset (computer science), 010504 meteorology & atmospheric sciences, Infrared, Dust particles, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Rosetta, 0103 physical sciences, Comets, Dust, Parallax, Stereo observations, Astronomy and Astrophysics, Space and Planetary Science, comets, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Remote sensing, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Spacecraft, biology, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], business.industry, 520 Astronomy, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, biology.organism_classification, 620 Engineering, stereo observations, Computer Science::Computer Vision and Pattern Recognition, Physics::Space Physics, 67 P/Churyumov-Gerasimenko, dust, Astrophysics::Earth and Planetary Astrophysics, Osiris, business, Astrophysics - Earth and Planetary Astrophysics
Abstract: International audience; The ESA Rosetta spacecraft has been tracking its target, the Jupiter-family comet 67 P/Churyumov-Gerasimenko, in close vicinity for over two years. It hosts the OSIRIS instruments: the Optical, Spectroscopic, and Infrared Remote Imaging System composed of two cameras, see e.g. Keller et al. (2007). In some imaging sequences dedicated to observe dust particles in the comet's coma, the two cameras took images at the same time.The aim of this work is to use these simultaneous double camera observations to calculate the dust particles’ distance to the spacecraft. As the two cameras are mounted on the spacecraft with an offset of 70 cm, the distance of particles observed by both cameras can be determined by a shift of the particles’ apparent trails on the images. This paper presents first results of the ongoing work, introducing the distance determination method for the OSIRIS instrument and the analysis of an example particle. We note that this method works for particles in the range of about 500 m – 6000 m from the spacecraft.
Published: 2017
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