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101. Physical properties of craters on asteroid (21) Lutetia

Author

Jean-Baptiste, Vincent, Sébastien, Besse, Marchi, Simone, Holger, Sierks, Massironi, Matteo, A’Hearn, The OSIRIS Team (M., Angrilli, F., Barbieri, C., Barucci, A., Bertaux, J. -L., Cremonese, G., Da Deppo, V., Davidsson, B., Debei, S., De Cecco, M., Fornasier, S., Fulle, M., Groussin, O., Gutierrez, P., Hviid, S. F., W. -H., Ip, Jorda, L., Keller, H. U., Koschny, D., Knollenberg, J., Kramm, J. R., Kuehrt, E., Lamy, P., Lara, L. M., Lazzarin, M., Lopez-Moreno, J. J., Marzari, F., Michalik, H., Naletto, G., Rickman, H., Rodrigo, R., Sabau, L., Thomas, N., and Wenzel), K. -P.

Subjects
Spacecraft, business.industry, Asteroid, Astronomy and Astrophysics, Geophysics, Lutetia, Regolith, Astrobiology, Impact crater, Craters morphology, Space and Planetary Science, Ejecta blanket, Ejecta, Scale (map), business, Event (particle physics), Geology
Abstract

This paper presents an analysis of the physical properties of craters on asteroid (21) Lutetia, derived from images acquired by OSIRIS, the high-resolution cameras onboard ESA's spacecraft Rosetta. Crater morphology on (21) Lutetia fits very well with the general picture of what was known for previously visited small bodies, with a typical depth to diameter ratio of 0.12. We discuss here the distribution of this parameter all across the surface, but also region by region, and see how it can vary from one location to another and help to distinguish between different geological units. In a later section of the paper we study in more details Beatica region where a deep ejecta blanket filled most of the craters, and estimate the thickness profile of this ejecta based on our analysis of the d / D . We find a good agreement with existing scaling laws, and use this to constrain the scale of the original event that reshaped the surface around the North pole of the asteroid. Finally, we report on the observations of avalanches in several crater flanks, and the presence of many asymmetrical craters with flow-like features, and discuss the evidence for widespread fine material all over the surface.

Published
2012
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102. The geomorphology of (21) Lutetia: Results from the OSIRIS imaging system onboard ESA's Rosetta spacecraft

Author

Thomas N., Barbieri C., Keller H. U., Lamy P., Rickman H., Rodrigo R., Sierks H., Wenzel K. P., Cremonese G., Jorda L., Kueppers M., Marchi S., Marzari F., Massironi M., Preusker F., Scholten F., Stephan K., Barucci M. A., Besse S., El-Maarry M. R., Fornasier S., Groussin O., Hviid S. F., Koschny D., and Kuehrt E.

Abstract

The surface of (21) Lutetia is highly complex with significant interactions between ancient and more recent structures. This work attempts to summarize the surface geomorphology observed using the high resolution images from OSIRIS the imaging system onboard the European Space Agency's Rosetta spacecraft. A wide range of surface morphologies are seen including heavily cratered terrain extensive sets of lineaments young impact craters and a ridge the height of which is more than 1/5th of the mean radius of the body. Very young and very old terrains (as inferred from crater densities) are seen in close proximity. The longest continuous lineament is over 80 km long. The lineaments show regional dependent organization and structure. Several categories of lineament can be described. Lineaments radial to impact craters as seen on other asteroidal bodies are mostly absent. Although the lineaments may be of seismic origin (and possibly the result of several impact induced events) impacts producing recent large craters place constraints on seismic phenomena. In particular stronger attenuation of shocks than seen on other asteroidal bodies seems to be required. Inhomogeneous energy transport possibly matching observed inhomogeneous ejecta deposition may offer explanations for some of the observed phenomena. Some impact craters show unusual forms which are probably the result of impact into a surface with relief comparable to the resultant crater diameter and/or oblique impact. There is evidence that re surfacing through landslides has occurred at several places on the object. (C) 2011 Elsevier Ltd. All rights reserved.

Published
2012

103. Preliminary calibration results of the wide angle camera of the imaging instrument OSIRIS for the Rosetta mission

Author

Da Deppo, V., primary, Nicolosi, P., primary, Ramous, P., primary, Verani, S., primary, Sebastian, I., primary, Angrilli, F., primary, Rickman, H., primary, Naletto, G., primary, Zambolin, P., primary, De Cecco, M., primary, Debei, S., primary, Parzianello, G., primary, Zaccariotto, M., primary, Fornasier, S., primary, Thomas, N., primary, Barthol, P., primary, Hviid, S. F., primary, Meller, R., primary, Sierks, H., primary, Keller, H. U., primary, Barbieri, C., primary, Lamy, P., primary, Rodrigo, R., primary, and Wenzel, K. P., primary

Published
2017
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105. 67P/Churyumov-Gerasimenko: Activity between March and June 2014 as observed from Rosetta/OSIRIS

Author

Tubiana, C., Snodgrass, C., Bertini, I., Mottola, S., Vincent, J.-B., Lara, L., Fornasier, S., Knollenberg, J., Thomas, N., Fulle, M., Agarwal, J., Bodewits, Dennis, Ferri, F., Güttler, C., Gutierrez, P. J., La Forgia, F., Lowry, S., Magrin, S., Oklay, N., Pajola, M., Rodrigo, R., Sierks, H., A'Hearn, Michael F., Angrilli, F., Barbieri, C., Barucci, M. A., Bertaux, Jean-Loup, Cremonese, Gabriele, Da Deppo, V., Davidsson, B., De Cecco, M., Debei, S., Groussin, O., Hviid, S. F., Ip, W., Jorda, L., Keller, H. U., Koschny, D., Kramm, R., Kührt, Ekkehard, Küppers, M., Lazzarin, M., Lamy, P. L., Lopez Moreno, J. J., Marzari, F., Michalik, H., Naletto, G., Rickman, H., Sabau, L., Wenzel, K.-P., Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, 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), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Universita degli Studi di Padova, DLR Institute of Planetary Research, German Aerospace Center (DLR), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), 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), Physikalisches Institut [Bern], Universität Bern [Bern], INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), 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', Centre for Astrophysics and Planetary Science [Canterbury] (CAPS), University of Kent [Canterbury], International Space Science Institute [Bern] (ISSI), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), 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), Department of Physics and Astronomy [Uppsala], Uppsala University, Università degli Studi di Trento (UNITN), Department of Industrial Engineering [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), 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], Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), European Space Astronomy Centre (ESAC), European Space Agency (ESA), Dipartimento di Fisica [Padova], Institut für Datentechnik und Kommunikationsnetze, Department of Information Engineering [Padova] (DEI), and Instituto Nacional de Técnica Aeroespacial (INTA)

Subjects
[SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP]
Abstract

International audience; 67P/Churyumov-Gerasimenko is the target comet of the ESA’s Rosetta mission. After commissioning at the end of March 2014, the Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) onboard Rosetta, started imaging the comet and its dust environment to investigate how they change and evolve while approaching the Sun.Methods. We focused our work on Narrow Angle Camera (NAC) orange images and Wide Angle Camera (WAC) red and visible-610 images acquired between 2014 March 23 and June 24 when the nucleus of 67P was unresolved and moving from approximately 4.3 AU to 3.8 AU inbound. During this period the 67P – Rosetta distance decreased from 5 million to 120 thousand km.Results. Through aperture photometry, we investigated how the comet brightness varies with heliocentric distance. 67P was likely already weakly active at the end of March 2014, with excess flux above that expected for the nucleus. The comet’s brightness was mostly constant during the three months of approach observations, apart from one outburst that occurred around April 30 and a second increase in flux after June 20. Coma was resolved in the profiles from mid-April. Analysis of the coma morphology suggests that most of the activity comes from a source towards the celestial north pole of the comet, but the outburst that occurred on April 30 released material in a different direction.

Published
2015
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106. Evolution Of The Dust Size Distribution Of Comet 67P/Churyumov-Gerasimenko From 2.2 Au To Perihelion

Author

Fulle, M., Marzari, F., Della Corte, V., Fornasier, S., Sierks, H., Rotundi, A., Barbieri, C., Lamy, P. L., Rodrigo, R., Koschny, D., Rickman, Hans, Keller, H. U., Lopez-Moreno, J. J., Accolla, M., Agarwal, J., A'Hearn, M. F., Altobelli, N., Barucci, M. A., Bertaux, J. -L, Bertini, I., Bodewits, D., Bussoletti, E., Colangeli, L., Cosi, M., Cremonese, G., Crifo, J. -F, Da Deppo, V., Davidsson, Björn, Debei, S., De Cecco, M., Esposito, F., Ferrari, M., Giovane, F., Gustafson, B., Green, S. F., Groussin, O., Gruen, E., Gutierrez, P., Guettler, C., Herranz, M. L., Hviid, S. F., Ip, W., Ivanovski, S. L., Jeronimo, J. M., Jorda, L., Knollenberg, J., Kramm, R., Kuehrt, E., Kueppers, M., Lara, L., Lazzarin, M., Leese, M. R., Lopez-Jimenez, A. C., Lucarelli, F., Epifani, E. Mazzotta, McDonnell, J. A. M., Mennella, V., Molina, A., Morales, R., Moreno, F., Mottola, S., Naletto, G., Oklay, N., Ortiz, J. L., Palomba, E., Palumbo, P., Perrin, J. -M, Rietmeijer, F. J. M., Rodriguez, J., Sordini, R., Thomas, N., Tubiana, C., Vincent, J. -B, Weissman, P., Wenzel, K. -P, Zakharov, V., Zarnecki, J. C., Fulle, M., Marzari, F., Della Corte, V., Fornasier, S., Sierks, H., Rotundi, A., Barbieri, C., Lamy, P. L., Rodrigo, R., Koschny, D., Rickman, Hans, Keller, H. U., Lopez-Moreno, J. J., Accolla, M., Agarwal, J., A'Hearn, M. F., Altobelli, N., Barucci, M. A., Bertaux, J. -L, Bertini, I., Bodewits, D., Bussoletti, E., Colangeli, L., Cosi, M., Cremonese, G., Crifo, J. -F, Da Deppo, V., Davidsson, Björn, Debei, S., De Cecco, M., Esposito, F., Ferrari, M., Giovane, F., Gustafson, B., Green, S. F., Groussin, O., Gruen, E., Gutierrez, P., Guettler, C., Herranz, M. L., Hviid, S. F., Ip, W., Ivanovski, S. L., Jeronimo, J. M., Jorda, L., Knollenberg, J., Kramm, R., Kuehrt, E., Kueppers, M., Lara, L., Lazzarin, M., Leese, M. R., Lopez-Jimenez, A. C., Lucarelli, F., Epifani, E. Mazzotta, McDonnell, J. A. M., Mennella, V., Molina, A., Morales, R., Moreno, F., Mottola, S., Naletto, G., Oklay, N., Ortiz, J. L., Palomba, E., Palumbo, P., Perrin, J. -M, Rietmeijer, F. J. M., Rodriguez, J., Sordini, R., Thomas, N., Tubiana, C., Vincent, J. -B, Weissman, P., Wenzel, K. -P, Zakharov, V., and Zarnecki, J. C.

Abstract

The Rosetta probe, orbiting Jupiter-family comet 67P/Churyumov-Gerasimenko, has been detecting individual dust particles of mass larger than 10(-10) kg by means of the GIADA dust collector and the OSIRIS Wide Angle Camera and Narrow Angle Camera since 2014 August and will continue until 2016 September. Detections of single dust particles allow us to estimate the anisotropic dust flux from 67P, infer the dust loss rate and size distribution at the surface of the sunlit nucleus, and see whether the dust size distribution of 67P evolves in time. The velocity of the Rosetta orbiter, relative to 67P, is much lower than the dust velocity measured by GIADA, thus dust counts when GIADA is nadir-pointing will directly provide the dust flux. In OSIRIS observations, the dust flux is derived from the measurement of the dust space density close to the spacecraft. Under the assumption of radial expansion of the dust, observations in the nadir direction provide the distance of the particles by measuring their trail length, with a parallax baseline determined by the motion of the spacecraft. The dust size distribution at sizes > 1 mm observed by OSIRIS is consistent with a differential power index of -4, which was derived from models of 67P's trail. At sizes <1 mm, the size distribution observed by GIADA shows a strong time evolution, with a differential power index drifting from -2 beyond 2 au to -3.7 at perihelion, in agreement with the evolution derived from coma and tail models based on ground-based data. The refractory-to-water mass ratio of the nucleus is close to six during the entire inbound orbit and at perihelion.

Published
2016
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108. EVOLUTION OF THE DUST SIZE DISTRIBUTION OF COMET 67P/CHURYUMOV–GERASIMENKO FROM 2.2 au TO PERIHELION

Author

Fulle, M., primary, Marzari, F., additional, Della Corte, V., additional, Fornasier, S., additional, Sierks, H., additional, Rotundi, A., additional, Barbieri, C., additional, Lamy, P. L., additional, Rodrigo, R., additional, Koschny, D., additional, Rickman, H., additional, Keller, H. U., additional, López-Moreno, J. J., additional, Accolla, M., additional, Agarwal, J., additional, A’Hearn, M. F., additional, Altobelli, N., additional, Barucci, M. A., additional, Bertaux, J.-L., additional, Bertini, I., additional, Bodewits, D., additional, Bussoletti, E., additional, Colangeli, L., additional, Cosi, M., additional, Cremonese, G., additional, Crifo, J.-F., additional, Da Deppo, V., additional, Davidsson, B., additional, Debei, S., additional, De Cecco, M., additional, Esposito, F., additional, Ferrari, M., additional, Giovane, F., additional, Gustafson, B., additional, Green, S. F., additional, Groussin, O., additional, Grün, E., additional, Gutierrez, P., additional, Güttler, C., additional, Herranz, M. L., additional, Hviid, S. F., additional, Ip, W., additional, Ivanovski, S. L., additional, Jerónimo, J. M., additional, Jorda, L., additional, Knollenberg, J., additional, Kramm, R., additional, Kührt, E., additional, Küppers, M., additional, Lara, L., additional, Lazzarin, M., additional, Leese, M. R., additional, López-Jiménez, A. C., additional, Lucarelli, F., additional, Mazzotta Epifani, E., additional, McDonnell, J. A. M., additional, Mennella, V., additional, Molina, A., additional, Morales, R., additional, Moreno, F., additional, Mottola, S., additional, Naletto, G., additional, Oklay, N., additional, Ortiz, J. L., additional, Palomba, E., additional, Palumbo, P., additional, Perrin, J.-M., additional, Rietmeijer, F. J. M., additional, Rodríguez, J., additional, Sordini, R., additional, Thomas, N., additional, Tubiana, C., additional, Vincent, J.-B., additional, Weissman, P., additional, Wenzel, K.-P., additional, Zakharov, V., additional, and Zarnecki, J. C., additional

Published
2016
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114. Book reviews

Author

de Jager, C., Sehnal, L., Kleczek, Josip, Vanysek, V., Quenby, J. J., van Duinen, R. J., van Gent, R. H., Kaastra, J. S., Ringeard, G., Mewe, R., Stiller, H., Wäsch, R., Wenzel, K. -P., Vrijer, A., Ceplecha, Z., Hellings, P., and Houziaux, L.

Published
1982
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120. Spectrophotometric investigation of Phobos with the Rosetta OSIRIS-NAC camera and implications for its collisional capture

Author

Pajola, M, Lazzarin, M, Bertini, I, Marzari, F, Turrini, D., Magrin, S, La Forgia, F, Thomas, N, Küppers, M, Moissl, R, Ferri, F, Barbieri, C, Rickman, H, Sierks, H, A’Hearn, Osiris Team (M., Angrilli, F., Barucci, A., Bertaux, J. -L., Cremonese, G., Davidsson, B., Da Deppo, V., Debei, S., De Cecco, M., Fornasier, S., Fulle, M., Groussin, O., Gutierrez, P., Hviid, S., W. -H., Ip, Jorda, L., Keller, H. U., Knollenberg, J., Koschny, D., Kramm, J. R., Kuehrt, E., Lamy, P., Lara, L. M., Lopez-Moreno, J. J., Michalik, H., Naletto, G., Rodrigo, R., Sabau, L., and Wenzel), K. -P.

Subjects
Solar System, 530 Physics, Mars, Context (language use), Individual, Spectral line, Rosetta Space Mission, Phobos, Phase angle (astronomy), Planet, Spectral slope, Formation -planets and satellites, Imaging spectroscopy -planets and satellites, Phobos -planets and satellites, Surfaces, Techniques, Physics, 520 Astronomy, Astronomy, Osiris images, Astronomy and Astrophysics, Mars Exploration Program, 620 Engineering, Space and Planetary Science, Asteroid
Abstract

The Martian satellite Phobos has been observed on 2007 February 24 and 25, during the pre- and post-Mars closest approach (CA) of the ESA Rosetta spacecraft Mars swing-by. The goal of the observations was the determination of the surface composition of different areas of Phobos, in order to obtain new clues regarding its nature and origin. Near-ultraviolet, visible and near-infrared (263.5–992.0 nm) images of Phobos's surface were acquired using the Narrow Angle Camera of the OSIRIS instrument onboard Rosetta. The six multi-wavelength sets of observations allowed a spectrophotometric characterization of different areas of the satellite, belonging respectively to the leading and trailing hemisphere of the anti-Mars hemisphere, and also of a section of its sub-Mars hemisphere. The pre-CA spectrophotometric data obtained with a phase angle of 19° have a spectral trend consistent within the error bars with those of unresolved/disc-integrated measurements present in the literature. In addition, we detect an absorption band centred at 950 nm, which is consistent with the presence of pyroxene. The post-CA observations cover from NUV to NIR a portion of the surface (0° to 43°E of longitude) never studied before. The reflectance measured on our data does not fit with the previous spectrophotometry above 650 nm. This difference can be due to two reasons. First, the OSIRIS observed area in this observation phase is completely different with respect to the other local specific spectra and hence the spectrum may be different. Secondly, due to the totally different observation geometry (the phase angle ranges from 137° to 140°), the differences of spectral slope can be due to phase reddening. The comparison of our reflectance spectra, both pre- and post-CA, with those of D-type asteroids shows that the spectra of Phobos are all redder than the mean D-type spectrum, but within the spectral dispersion of other D-types. To complement this result, we performed an investigation of the conditions needed to collisionally capture Phobos in a way similar to that proposed for the irregular satellites of the giant planets. Once put in the context of the current understanding of the evolution of the early Solar system, the coupled observational and dynamical results we obtained strongly argue for an early capture of Phobos, likely immediately after the formation of Mars.

Published
2012
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121. Hydrocode simulations of the largest crater on asteroid Lutetia

Author

Cremonese, G., Martellato, E., Marzari, F., Kuhrt, E, Scholten, F., Preusker, F., Wünnemann, K., Borin, P., Massironi, M., Simioni, E, Ip, W., A’Hearn, and the OSIRIS Team (M., Angrilli, F., Barbieri, C., Barucci, A., Bertaux, J. -L., Da Deppo, V., Davidsson, B., Debei, S., Dececco, M., Fornasier, S., Fulle, M., Groussin, O., Gutierrez, P., Hviid, S. F., Jorda, L., Keller, H. U., Koschny, D., Knollemberg, J., Kramm, J. R., Lamy, P., Lara, L. M., Lazzarin, M., Lopez-Moreno, J. J., Michalik, H., Naletto, G., Rickman, H., Rodrigo, R., Sabau, L., Sierks, H., Thomas, N., and Wenzel), K. -P.

Subjects
North pole, Astronomy, Numerical modeling, Astronomy and Astrophysics, Geodesy, Lutetia, Asteroids, Impact crater, Space and Planetary Science, Asteroid, Impacts, Rosetta, Impact structure, Digital elevation model, Geology, Cratering
Abstract

The flyby of the Main Belt asteroid Lutetia by the Rosetta spacecraft allows the camera OSIRIS to obtain very good images of about half of the body at the maximum resolution of 60 m per pixel. From the images and radio-science experiment, a density of about (3.4±0.3) g/cm3 has been inferred for the asteroid. Many impact craters have been observed on the surface of Lutetia and the largest, named Massilia, has a diameter of about 55 km. Relative to the size of Lutetia (the longest axis is approximately 126 km) the crater represents one of the dominating features on its surface. Whether or not the impact that formed Massilia affected the entire asteroid can be only evaluated via numerical modeling, with hydrocodes, of the impact process. The results of a suite of iSALE simulations are compared with the crater profile derived from the Digital Terrain Model of the observed surface. The best match to the DTM of the crater with hydrocode simulations has allowed to determine a value of 7.5 km for the impactor diameter, which suggests a primordial origin of Lutetia due to the low probability of such an impact event. A second interesting impact structure has been identified nearby Massilia within the North Pole Crater Cluster. The crater has a diameter of 24 km and it lies over a larger crater of the North Pole Crater Cluster. This is strongly suggestive of a very young structure on Lutetia. The numerical simulations of this feature constrain the impactor to be 3.8 km in diameter, assuming the same material properties for target and impactor as in the model of the formation of Massilia.

Published
2012

122. Boulders on Lutetia

Author

Küppers, Michael, Moissl, Richard, Vincent, Jean-Baptiste, Besse, Sébastien, Hviid, Stubbe F., Carry, Benoît, Grieger, Björn, Sierks, Holger, Keller, Horst Uwe, Marchi, A’Hearn, Simone (M., Angrilli, F., Barbieri, C., Barucci, A., Bertaux, J. -L., Cremonese, G., Da Deppo, V., Davidsson, B., Debei, S., De Cecco, M., Fornasier, S., Fulle, M., Groussin, O., Gutierrez, P., W. -H., Ip, Jorda, L., Koschny, D., Knollenberg, J., Kramm, J. R., Kuhrt, E., Lamy, P., Lara, L. M., Lazzarin, M., Lopez-Moreno, J. J., Marzari, F., Michalik, H., Naletto, G., Rickman, H., Rodrigo, R., Sabau, L., Thomas, N., and Wenzel), K. -P.

Subjects
biology, Astronomy and Astrophysics, biology.organism_classification, Lutetia, Astrobiology, Imaging, Boulders, Cratering, Space and Planetary Science, Impact crater, Asteroid, Osiris, Ejecta, Geology
Abstract

More than 200 boulders are among the many prominent geological features seen on Lutetia by the OSIRIS cameras onboard Rosetta. Most are concentrated around the central crater in Baetica regio with a few more apparently associated with Patavium crater. The size range of boulders visible to OSIRIS is about 60–300 m. We model the trajectories of boulders ejected from the central crater and show that their distribution is consistent with most of them being created from that crater, similar to the situation on asteroid Eros where most of the boulders are believed to originate from Shoemaker crater. We evaluate various destruction mechanisms for ejecta blocks and conclude that, using current estimates of the number of small asteroids in the main belt, destruction by impacts of small (several meters diameter) projectiles limits the lifetime of the boulders (and the age of the central crater) to a maximum of 300 million years. Since several analyses of crater ages and size distributions also come up with surprisingly young ages, the size-frequency distribution of small main-belt asteroids (below the size currently reached by surveys) may warrant to be revisited.

Published
2012

123. (21) Lutetia spectrophotometry from Rosetta-OSIRIS images and comparison to ground-based observations

Author

Magrin, S., La Forgia, F., Pajola, Maurizio, Lazzarin, M., Massironi, M., Ferri, F., Da Deppo, V., Barbieri, C., Sierks, H., A’Hearn, OSIRIS Team (M., Angrilli, F., Barucci, A., Bertaux, J. -L., Cremonese, G., Davidsson, B., Debei, S., De Cecco, M., Fornasier, S., Fulle, M., Groussin, O., Gutierrez, P., Hviid, S., W. -H., Ip, Jorda, L., Keller, H. U., Knollenberg, J., Koschny, D., Kramm, J. R., Kuehrt, E., Kuppers, M., Lamy, P., Lara, L. M., Lopez-Moreno, J. J., Marzari, F., Michalik, H., Naletto, G., Rickman, H., Rodrigo, R., Sabau, L., Thomas, N., Weissman, P. r., and Wenzel), K. -P.

Subjects
Physics, medicine.diagnostic_test, biology, Data error, Minor bodies, Lutetia Asteroid, Astronomy and Astrophysics, Astrophysics, Lutetia, biology.organism_classification, Space and Planetary Science, Asteroid, Spectrophotometry, Variegation (histology), Rosetta, medicine, spectrophotometry, OSIRIS, Osiris, Remote sensing
Abstract

Here we present some preliminary results on surface variegation found on (21) Lutetia from ROSETTA-OSIRIS images acquired on 2010-07-10. The spectrophotometry obtained by means of the two cameras NAC and WAC (Narrow and Wide Angle Cameras) is consistent with ground based observations, and does not show surface diversity above the data error bars. The blue and UV images (shortward 500 nm) may, however, indicate a variegation of the optical properties of the asteroid surface on the Baetica region (Sierks et al., 2011). We also speculate on the contribution due to different illumination and to different ground properties (composition or, more probably, grain size diversity). In particular a correlation with geologic units independently defined by Massironi et al. (2012) is evident, suggesting that the variegation of the ground optical properties is likely to be real. © 2011 Elsevier Ltd.

Published
2012
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125. Shape modeling technique KOALA validated by ESA Rosetta at (21) Lutetia

Author

Carry, B., Kaasalainen, M., Merline, W. J., Müller, T. G., Jorda, L., Drummond, J. D., Berthier, J., O'Rourke, L., Urech, J., Küppers, M., Conrad, A., Tamblyn, P., Dumas, C., Sierks, A’Hearn, H. (M., Angrilli, F., Barbieri, C., Barucci, A., Bertaux, J. -L., Cremonese, G., Da Deppo, V., Davidsson, B., Debei, S., De Cecco, M., Fornasier, S., Fulle, M., Groussin, O., Gutierrez, P., W. -H., Ip, Hviid, S., Keller, H. U., Koschny, D., Knollenberg, J., Kramm, J. R., Kuehrt, E., Lamy, P., Lara, L. M., Lazzarin, M., Lopez-Moreno, J. J., Marzari, F., Michalik, H., Naletto, G., Rickman, H., Rodrigo, R., Sabau, L., Thomas, N., Wenzel), K. -P., European Space Astronomy Centre (ESAC), European Space Agency (ESA), Department of Mathematics [Tampere], Tampere University of Technology [Tampere] (TUT), Department of Space Studies [Boulder], Southwest Research Institute [Boulder] (SwRI), Max-Planck-Institut für Extraterrestrische Physik (MPE), 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), Starfire Optical Range [AFRL] (SOR), United States Air Force (USAF), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Centre National de la Recherche Scientifique (CNRS)-Université de Lille-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), Astronomical Institute of Charles University, Charles University [Prague] (CU), Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, European Southern Observatory (ESO), Max-Planck-Institut für Sonnensystemforschung (MPS), Agence Spatiale Européenne = European Space Agency (ESA), 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 de Lille-Centre National de la Recherche Scientifique (CNRS), Groupe Astrométrie et Planétologie (GAP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Tampere University of Technology (TUT), Southwest Research Institute, Max-Planck-Institut für Extraterrestriche Physik (MPE), 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), Starfire Optical Range, Directed Energy Directorate, Air Force Research Laboratory, Kirtland AFB, Astronomical Institute, Charles University, European Southern Observatory, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), European Space Astronomy Centre, Tampere University of Technology [Tampere] ( TUT ), Southwest Research Institute [Boulder] ( SwRI ), Max-Planck-Institut für Extraterrestrische Physik ( MPE ), 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'Etudes Spatiales ( CNES ), Starfire Optical Range [AFRL] ( SOR ), United States Air Force ( USAF ), Institut de Mécanique Céleste et de Calcul des Ephémérides ( IMCCE ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire de Paris-Université de Lille-Centre National de la Recherche Scientifique ( CNRS ), Charles University [Prague], Max-Planck-Institut für Astronomie ( MPIA ), European Southern Observatory ( ESO ), and Max-Planck-Institut für Sonnensystemforschung ( MPS )

Subjects
(21) Lutetia, 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Astrophysics, 01 natural sciences, Imaging data, Occultation, Space exploration, Geometric albedo, 0103 physical sciences, Rosetta, KOALA, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Remote sensing, Earth and Planetary Astrophysics (astro-ph.EP), biology, Spacecraft, Asteroid, Disk-resolved imaging, Astronomy and Astrophysics, Space and Planetary Science, business.industry, Astronomy, Observable, biology.organism_classification, [ SDU.ASTR.EP ] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [ PHYS.ASTR.EP ] Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Earth and Planetary Astrophysics, Osiris, business, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Geology, Astrophysics - Earth and Planetary Astrophysics
Abstract

We present a comparison of our results from ground-based observations of asteroid (21) Lutetia with imaging data acquired during the flyby of the asteroid by the ESA Rosetta mission. This flyby provided a unique opportunity to evaluate and calibrate our method of determination of size, 3-D shape, and spin of an asteroid from ground-based observations. We present our 3-D shape-modeling technique KOALA which is based on multi-dataset inversion. We compare the results we obtained with KOALA, prior to the flyby, on asteroid (21) Lutetia with the high-spatial resolution images of the asteroid taken with the OSIRIS camera on-board the ESA Rosetta spacecraft, during its encounter with Lutetia. The spin axis determined with KOALA was found to be accurate to within two degrees, while the KOALA diameter determinations were within 2% of the Rosetta-derived values. The 3-D shape of the KOALA model is also confirmed by the spectacular visual agreement between both 3-D shape models (KOALA pre- and OSIRIS post-flyby). We found a typical deviation of only 2 km at local scales between the profiles from KOALA predictions and OSIRIS images, resulting in a volume uncertainty provided by KOALA better than 10%. Radiometric techniques for the interpretation of thermal infrared data also benefit greatly from the KOALA shape model: the absolute size and geometric albedo can be derived with high accuracy, and thermal properties, for example the thermal inertia, can be determined unambiguously. We consider this to be a validation of the KOALA method. Because space exploration will remain limited to only a few objects, KOALA stands as a powerful technique to study a much larger set of small bodies using Earth-based observations., 15 pages, 8 figures, 2 tables, accepted for publication in P&SS

Published
2011
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126. Comet 67P/Churyumov-Gerasimenko : Constraints on its origin from OSIRIS observations

Author

Rickman, Hans, Marchi, S., A'Hearn, M. F., Barbieri, C., El-Maarry, M. R., Guettler, C., Ip, W. -H, Keller, H. U., Lamy, P., Marzari, F., Massironi, M., Naletto, G., Pajola, M., Sierks, H., Koschny, D., Rodrigo, R., Barucci, M. A., Bertaux, J. -L, Bertini, I., Cremonese, G., Da Deppo, V., Debei, S., De Cecco, M., Fornasier, S., Fulle, M., Groussin, O., Gutierrez, P. J., Hviid, S. F., Jorda, L., Knollenberg, J., Kramm, J. -R, Kuehrt, E., Kueppers, M., Lara, L. M., Lazzarin, M., Lopez Moreno, J. J., Michalik, H., Sabau, L., Thomas, N., Vincent, J. -B, Wenzel, K. -P, Rickman, Hans, Marchi, S., A'Hearn, M. F., Barbieri, C., El-Maarry, M. R., Guettler, C., Ip, W. -H, Keller, H. U., Lamy, P., Marzari, F., Massironi, M., Naletto, G., Pajola, M., Sierks, H., Koschny, D., Rodrigo, R., Barucci, M. A., Bertaux, J. -L, Bertini, I., Cremonese, G., Da Deppo, V., Debei, S., De Cecco, M., Fornasier, S., Fulle, M., Groussin, O., Gutierrez, P. J., Hviid, S. F., Jorda, L., Knollenberg, J., Kramm, J. -R, Kuehrt, E., Kueppers, M., Lara, L. M., Lazzarin, M., Lopez Moreno, J. J., Michalik, H., Sabau, L., Thomas, N., Vincent, J. -B, and Wenzel, K. -P

Abstract

Context. One of the main aims of the ESA Rosetta mission is to study the origin of the solar system by exploring comet 67P/Churyumov-Gerasimenko at close range. Aims. In this paper we discuss the origin and evolution of comet 67P/Churyumov-Gerasimenko in relation to that of comets in general and in the framework of current solar system formation models. Methods. We use data from the OSIRIS scientific cameras as basic constraints. In particular, we discuss the overall bi-lobate shape and the presence of key geological features, such as layers and fractures. We also treat the problem of collisional evolution of comet nuclei by a particle-in-a-box calculation for an estimate of the probability of survival for 67P/Churyumov-Gerasimenko during the early epochs of the solar system. Results. We argue that the two lobes of the 67P/Churyumov-Gerasimenko nucleus are derived from two distinct objects that have formed a contact binary via a gentle merger. The lobes are separate bodies, though sufficiently similar to have formed in the same environment. An estimate of the collisional rate in the primordial, trans-planetary disk shows that most comets of similar size to 67P/Churyumov-Gerasimenko are likely collisional fragments, although survival of primordial planetesimals cannot be excluded. Conclusions. A collisional origin of the contact binary is suggested, and the low bulk density of the aggregate and abundance of volatile species show that a very gentle merger must have occurred. We thus consider two main scenarios: the primordial accretion of planetesimals, and the re-accretion of fragments after an energetic impact onto a larger parent body. We point to the primordial signatures exhibited by 67P/Churyumov-Gerasimenko and other comet nuclei as critical tests of the collisional evolution.

Published
2015
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127. Insolation, erosion, and morphology of comet 67P/Churyumov-Gerasimenko

Author

Keller, H. U., Mottola, S., Davidsson, Björn, Schroeder, S. E., Skorov, Y., Kuehrt, E., Groussin, O., Pajola, M., Hviid, S. F., Preusker, F., Scholten, F., A'Hearn, M. F., Sierks, H., Barbieri, C., Lamy, P., Rodrigo, R., Koschny, D., Rickman, Hans, Barucci, M. A., Bertaux, J. -L, Bertini, I., Cremonese, G., Da Deppo, V., Debei, S., De Cecco, M., Fornasier, S., Fulle, M., Gutierrez, P. J., Ip, W. -H, Jorda, L., Knollenberg, J., Kramm, J. R., Kueppers, M., Lara, L. M., Lazzarin, M., Lopez Moreno, J. J., Marzari, F., Michalik, H., Naletto, G., Sabau, L., Thomas, N., Vincent, J. -B, Wenzel, K. -P, Agarwal, J., Guettler, C., Oklay, N., Tubiana, C., Keller, H. U., Mottola, S., Davidsson, Björn, Schroeder, S. E., Skorov, Y., Kuehrt, E., Groussin, O., Pajola, M., Hviid, S. F., Preusker, F., Scholten, F., A'Hearn, M. F., Sierks, H., Barbieri, C., Lamy, P., Rodrigo, R., Koschny, D., Rickman, Hans, Barucci, M. A., Bertaux, J. -L, Bertini, I., Cremonese, G., Da Deppo, V., Debei, S., De Cecco, M., Fornasier, S., Fulle, M., Gutierrez, P. J., Ip, W. -H, Jorda, L., Knollenberg, J., Kramm, J. R., Kueppers, M., Lara, L. M., Lazzarin, M., Lopez Moreno, J. J., Marzari, F., Michalik, H., Naletto, G., Sabau, L., Thomas, N., Vincent, J. -B, Wenzel, K. -P, Agarwal, J., Guettler, C., Oklay, N., and Tubiana, C.

Abstract

Context. The complex shape of comet 67P and its oblique rotation axis cause pronounced seasonal effects. Irradiation and hence activity vary strongly. Aims. We investigate the insolation of the cometary surface in order to predict the sublimation of water ice. The strongly varying erosion levels are correlated with the topography and morphology of the present cometary surface and its evolution. Methods. The insolation as a function of heliocentric distance and diurnal (spin dependent) variation is calculated using >10(5) facets of a detailed digital terrain model. Shading, but also illumination and thermal radiation by facets in the field of view of a specific facet are iteratively taken into account. We use a two-layer model of a thin porous dust cover above an icy surface to calculate the water sublimation, presuming steady state and a uniform surface. Our second model, which includes the history of warming and cooling due to thermal inertia, is restricted to a much simpler shape model but allows us to test various distributions of active areas. Results. Sublimation from a dirty ice surface yields maximum erosion. A thin dust cover of 50 pm yields similar rates at perihelion. Only about 6% of the surface needs to be active to match the observed water production rates at perihelion. A dust layer of 1 mm thickness suppresses the activity by a factor of 4 to 5. Erosion on the south side can reach more than 10 m per orbit at active spots. The energy input to the concave neck area (Hapi) during northern summer is enhanced by about 50% owing to self-illumination. Here surface temperatures reach maximum values along the foot of the Hathor wall. Integrated over the whole orbit this area receives the least energy input. Based on the detailed shape model, the simulations identify "hot spots" in depressions and larger pits in good correlation with observed dust activity. Three-quarters of the total sublimation is produced while the sub-solar latitude is south, resulting i

Published
2015
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128. Rotating dust particles in the coma of comet 67P/Churyumov-Gerasimenko

Author

Fulle, M., Ivanovski, S. L., Bertini, I., Gutierrez, P., Lara, L., Sierks, H., Zakharov, V., Della Corte, V., Rotundi, A., Barbieri, C., Lamy, P. L., Rodrigo, R., Koschny, D., Rickman, Hans, Keller, H. U., Agarwal, J., A'Hearn, M. F., Barucci, M. A., Bertaux, J. -L, Bodewits, D., Cremonese, G., Da Deppo, V., Davidsson, Björn, Debei, S., De Cecco, M., Fornasier, S., Groussin, O., Guettler, C., Hviid, S. F., Ip, W., Jorda, L., Knollenberg, J., Kramm, R., Kuehrt, E., Kueppers, M., Lazzarin, M., Lopez-Moreno, J. J., Marzari, F., Michalik, H., Naletto, G., Oklay, N., Sabau, L., Thomas, N., Tubiana, C., Vincent, J. -B, Wenzel, K. -P, Fulle, M., Ivanovski, S. L., Bertini, I., Gutierrez, P., Lara, L., Sierks, H., Zakharov, V., Della Corte, V., Rotundi, A., Barbieri, C., Lamy, P. L., Rodrigo, R., Koschny, D., Rickman, Hans, Keller, H. U., Agarwal, J., A'Hearn, M. F., Barucci, M. A., Bertaux, J. -L, Bodewits, D., Cremonese, G., Da Deppo, V., Davidsson, Björn, Debei, S., De Cecco, M., Fornasier, S., Groussin, O., Guettler, C., Hviid, S. F., Ip, W., Jorda, L., Knollenberg, J., Kramm, R., Kuehrt, E., Kueppers, M., Lazzarin, M., Lopez-Moreno, J. J., Marzari, F., Michalik, H., Naletto, G., Oklay, N., Sabau, L., Thomas, N., Tubiana, C., Vincent, J. -B, and Wenzel, K. -P

Abstract

Context. During September and October 2014, the OSIRIS cameras onboard the ESA Rosetta mission detected millions of single particles. Many of these dust particles appear as long tracks (due to both the dust proper motion and the spacecraft motion during the exposure time) with a clear brightness periodicity. Aims. We interpret the observed periodic features as a rotational and translational motion of aspherical dust grains. Methods. By counting the peaks of each track, we obtained statistics of a rotation frequency. We compared these results with the rotational frequency predicted by a model of aspherical dust grain dynamics in a model gas flow. By testing many possible sets of physical conditions and grain characteristics, we constrained the rotational properties of dust grains. Results. We analyzed on the motion of rotating aspherical dust grains with different cross sections in flow conditions corresponding to the coma of 67P/Churyumov-Gerasimenko qualitatively and quantitatively. Based on the OSIRIS observations, we constrain the possible physical parameters of the grains.

Published
2015
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129. Geomorphology of the Imhotep region on comet 67P/Churyumov-Gerasimenko from OSIRIS observations

Author

Auger, A. -T, Groussin, O., Jorda, L., Bouley, S., Gaskell, R., Lamy, P. L., Capanna, C., Thomas, N., Pommerol, A., Sierks, H., Barbieri, C., Rodrigo, R., Koschny, D., Rickman, Hans, Keller, H. U., Agarwal, J., A'Hearn, M. F., Barucci, M. A., Bertaux, J. -L, Bertini, I., Cremonese, G., Da Deppo, V., Davidsson, Björn, Debei, S., De Cecco, M., El-Maarry, M. R., Fornasier, S., Fulle, M., Gutierrez, P. J., Guettler, C., Hviid, S., Ip, W. -H, Knollenberg, J., Kramm, J. -R, Kuehrt, E., Kueppers, M., La Forgia, F., Lara, L. M., Lazzarin, M., Lopez Moreno, J. J., Marchi, S., Marzari, F., Massironi, M., Michalik, H., Naletto, G., Oklay, N., Pajola, M., Sabau, L., Tubiana, C., Vincent, J. -B, Wenzel, K. -P, Auger, A. -T, Groussin, O., Jorda, L., Bouley, S., Gaskell, R., Lamy, P. L., Capanna, C., Thomas, N., Pommerol, A., Sierks, H., Barbieri, C., Rodrigo, R., Koschny, D., Rickman, Hans, Keller, H. U., Agarwal, J., A'Hearn, M. F., Barucci, M. A., Bertaux, J. -L, Bertini, I., Cremonese, G., Da Deppo, V., Davidsson, Björn, Debei, S., De Cecco, M., El-Maarry, M. R., Fornasier, S., Fulle, M., Gutierrez, P. J., Guettler, C., Hviid, S., Ip, W. -H, Knollenberg, J., Kramm, J. -R, Kuehrt, E., Kueppers, M., La Forgia, F., Lara, L. M., Lazzarin, M., Lopez Moreno, J. J., Marchi, S., Marzari, F., Massironi, M., Michalik, H., Naletto, G., Oklay, N., Pajola, M., Sabau, L., Tubiana, C., Vincent, J. -B, and Wenzel, K. -P

Abstract

Context. Since August 2014, the OSIRIS Narrow Angle Camera (NAC) onboard the Rosetta spacecraft has acquired high spatial resolution images of the nucleus of comet 67P/Churyumov-Gerasimenko, down to the decimeter scale. This paper focuses on the Imhotep region, located on the largest lobe of the nucleus, near the equator. Aims. We map, inventory, and describe the geomorphology of the Imhotep region. We propose and discuss some processes to explain the formation and ongoing evolution of this region. Methods. We used OSIRIS NAC images, gravitational heights and slopes, and digital terrain models to map and measure the morphologies of Imhotep. Results. The Imhotep region presents a wide variety of terrains and morphologies: smooth and rocky terrains, bright areas, linear features, roundish features, and boulders. Gravity processes such as mass wasting and collapse play a significant role in the geomorphological evolution of this region. Cometary processes initiate erosion and are responsible for the formation of degassing conduits that are revealed by elevated roundish features on the surface. We also propose a scenario for the formation and evolution of the Imhotep region; this implies the presence of large primordial voids inside the nucleus, resulting from its formation process.

Published
2015
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130. Insolation, erosion, and morphology of comet 67P/Churyumov-Gerasimenko

Author

Keller, H. U., primary, Mottola, S., additional, Davidsson, B., additional, Schröder, S. E., additional, Skorov, Y., additional, Kührt, E., additional, Groussin, O., additional, Pajola, M., additional, Hviid, S. F., additional, Preusker, F., additional, Scholten, F., additional, A’Hearn, M. F., additional, Sierks, H., additional, Barbieri, C., additional, Lamy, P., additional, Rodrigo, R., additional, Koschny, D., additional, Rickman, H., additional, Barucci, M. A., additional, Bertaux, J.-L., additional, Bertini, I., additional, Cremonese, G., additional, Da Deppo, V., additional, Debei, S., additional, De Cecco, M., additional, Fornasier, S., additional, Fulle, M., additional, Gutiérrez, P. J., additional, Ip, W.-H., additional, Jorda, L., additional, Knollenberg, J., additional, Kramm, J. R., additional, Küppers, M., additional, Lara, L. M., additional, Lazzarin, M., additional, Lopez Moreno, J. J., additional, Marzari, F., additional, Michalik, H., additional, Naletto, G., additional, Sabau, L., additional, Thomas, N., additional, Vincent, J.-B., additional, Wenzel, K.-P., additional, Agarwal, J., additional, Güttler, C., additional, Oklay, N., additional, and Tubiana, C., additional

Published
2015
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131. Rotating dust particles in the coma of comet 67P/Churyumov-Gerasimenko

Author

Fulle, M., primary, Ivanovski, S. L., additional, Bertini, I., additional, Gutierrez, P., additional, Lara, L., additional, Sierks, H., additional, Zakharov, V., additional, Della Corte, V., additional, Rotundi, A., additional, Barbieri, C., additional, Lamy, P. L., additional, Rodrigo, R., additional, Koschny, D., additional, Rickman, H., additional, Keller, H. U., additional, Agarwal, J., additional, A’Hearn, M. F., additional, Barucci, M. A., additional, Bertaux, J.-L., additional, Bodewits, D., additional, Cremonese, G., additional, Da Deppo, V., additional, Davidsson, B., additional, Debei, S., additional, De Cecco, M., additional, Fornasier, S., additional, Groussin, O., additional, Güttler, C., additional, Hviid, S. F., additional, Ip, W., additional, Jorda, L., additional, Knollenberg, J., additional, Kramm, R., additional, Kührt, E., additional, Küppers, M., additional, Lazzarin, M., additional, Lopez-Moreno, J. J., additional, Marzari, F., additional, Michalik, H., additional, Naletto, G., additional, Oklay, N., additional, Sabau, L., additional, Thomas, N., additional, Tubiana, C., additional, Vincent, J.-B., additional, and Wenzel, K.-P., additional

Published
2015
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132. Geomorphology of the Imhotep region on comet 67P/Churyumov-Gerasimenko from OSIRIS observations

Author

Auger, A.-T., primary, Groussin, O., additional, Jorda, L., additional, Bouley, S., additional, Gaskell, R., additional, Lamy, P. L., additional, Capanna, C., additional, Thomas, N., additional, Pommerol, A., additional, Sierks, H., additional, Barbieri, C., additional, Rodrigo, R., additional, Koschny, D., additional, Rickman, H., additional, Keller, H. U., additional, Agarwal, J., additional, A’Hearn, M. F., additional, Barucci, M. A., additional, Bertaux, J.-L., additional, Bertini, I., additional, Cremonese, G., additional, Da Deppo, V., additional, Davidsson, B., additional, Debei, S., additional, De Cecco, M., additional, El-Maarry, M. R., additional, Fornasier, S., additional, Fulle, M., additional, Gutiérrez, P. J., additional, Güttler, C., additional, Hviid, S., additional, Ip, W.-H., additional, Knollenberg, J., additional, Kramm, J.-R., additional, Kührt, E., additional, Küppers, M., additional, La Forgia, F., additional, Lara, L. M., additional, Lazzarin, M., additional, Lopez Moreno, J. J., additional, Marchi, S., additional, Marzari, F., additional, Massironi, M., additional, Michalik, H., additional, Naletto, G., additional, Oklay, N., additional, Pajola, M., additional, Sabau, L., additional, Tubiana, C., additional, Vincent, J.-B., additional, and Wenzel, K.-P., additional

Published
2015
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133. Comet 67P/Churyumov-Gerasimenko: Constraints on its origin from OSIRIS observations

Author

Rickman, H., primary, Marchi, S., additional, A’Hearn, M. F., additional, Barbieri, C., additional, El-Maarry, M. R., additional, Güttler, C., additional, Ip, W.-H., additional, Keller, H. U., additional, Lamy, P., additional, Marzari, F., additional, Massironi, M., additional, Naletto, G., additional, Pajola, M., additional, Sierks, H., additional, Koschny, D., additional, Rodrigo, R., additional, Barucci, M. A., additional, Bertaux, J.-L., additional, Bertini, I., additional, Cremonese, G., additional, Da Deppo, V., additional, Debei, S., additional, De Cecco, M., additional, Fornasier, S., additional, Fulle, M., additional, Groussin, O., additional, Gutiérrez, P. J., additional, Hviid, S. F., additional, Jorda, L., additional, Knollenberg, J., additional, Kramm, J.-R., additional, Kührt, E., additional, Küppers, M., additional, Lara, L. M., additional, Lazzarin, M., additional, Lopez Moreno, J. J., additional, Michalik, H., additional, Sabau, L., additional, Thomas, N., additional, Vincent, J.-B., additional, and Wenzel, K.-P., additional

Published
2015
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140. Evidence for a Large Dust/Ice Ratio in the Nucleus of Comet 9P/Tempel 1

Author

Küppers, Michael, Bertini, Ivano, Fornasier, Sonia, Gutierrez, Pedro J., Hviid, Stubbe F., Jorda, Laurent, Keller, Horst Uwe, Knollenberg, Jörg, Koschny, Detlef, Kramm, Rainer, Lara, Luisa-Maria, Sierks, Holger, Thomas, Nicolas, Barbieri, Cesare, Lamy, Philippe, Rickman, Hans, Rodrigo, Rafael, A'Hearn, M. F., Angrilli, F., Bailey, M. E., Barthol, P., Barucci, M. A., Bertaux, J.-L., Burns, J. A., Cremonese, G., Curdt, W., De Cecco, M., Debei, S., Fulle, M., Gliem, F., Ip, W.-H., Kührt, E., Llebaria, A., Lopez Moreno, J. J., Marzari, F., Naletto, G., Sabau, L., Sanz Andrés, A., Sivan, J. P., Tondello, G., and Wenzel, K.-P.

Subjects
Deep Impact, dust/ice ratio, comets
Published
2005

141. A large dust/ice ratio in the nucleus of comet 9P/Tempel 1

Author

Kueppers, M., Bertini, Ivano, Fornasier, Sonia, Gutierrez, P. J., Hviid, S. F., Jorda, L., Keller, H. U., Knollenberg, J., Koschny, D., Kramm, R., Lara, L. M., Sierks, H., Thomas, N., Barbieri, Cesare, Lamy, P., Rickman, H., Rodrigo, R., A'Hearn, M. F., Angrilli, F., Bailey, M. E., Barthol, P., Barucci, M. A., Bertaux, J. L., Burns, J. A., Cremonese, G., Curdt, W., DE CECCO, M., Debei, Stefano, Fulle, M., Gliem, F., W. H., Ip, Khrt, E., Llebaria, A., LOPEZ MORENO, J. J., Marzari, Francesco, Naletto, Giampiero, Sabau, L., SANZ ANDRS, A., Sivan, J. P., Tondello, Giuseppe, Wenzel, K. P., Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Dipartimento di Astronomia [Padova], 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), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Uppsala Astronomical 0bservatory (UAO), Uppsala University, Service d'aéronomie (SA), 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), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Università degli Studi di Padova = University of Padua (Unipd), and 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)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Multidisciplinary, 010504 meteorology & atmospheric sciences, Meteoroid, Comet tail, Comet dust, Comet, comete, Planetary system, 01 natural sciences, Astrobiology, Impact crater, Rosetta, OSIRIS, 13. Climate action, Comet nucleus, 0103 physical sciences, 010303 astronomy & astrophysics, Water vapor, Geology, 0105 earth and related environmental sciences
Abstract

NASA's Deep Impact spacecraft met its intended fate on 4 July this year when it collided with Comet Tempel 1 at a relative velocity of over 36,000 km per hour. Telescopes all around the world and beyond it were trained on the event in order to glean information about the internal structure of a comet. Results from OSIRIS cameras on ESA's Rosetta spacecraft provided continuous coverage from 3 days before to 10 days after the impact. The impact created a crater 60 metres in diameter and the nature of the debris points to the comet as an ‘icy dustball’ rather than the more familiar concept of a ‘dirty snowball’. Comets spend most of their life in a low-temperature environment far from the Sun. They are therefore relatively unprocessed and maintain information about the formation conditions of the planetary system, but the structure and composition of their nuclei are poorly understood. Although in situ1 and remote2 measurements have derived the global properties of some cometary nuclei, little is known about their interiors. The Deep Impact mission3 shot a projectile into comet 9P/Tempel 1 in order to investigate its interior. Here we report the water vapour content (1.5 × 1032 water molecules or 4.5 × 106 kg) and the cross-section of the dust (330 km2 assuming an albedo of 0.1) created by the impact. The corresponding dust/ice mass ratio is probably larger than one, suggesting that comets are ‘icy dirtballs’ rather than ‘dirty snowballs’ as commonly believed4. High dust velocities (between 110 m s-1 and 300 m s-1) imply acceleration in the comet's coma, probably by water molecules sublimated by solar radiation. We did not find evidence of enhanced activity of 9P/Tempel 1 in the days after the impact, suggesting that in general impacts of meteoroids are not the cause of cometary outbursts.

Published
2005
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145. The rotation state of 67P/Churyumov-Gerasimenko from approach observations with the OSIRIS cameras on Rosetta

Author

Mottola, S., Lowry, S., Snodgrass, C., Lamy, P. L., Toth, I., Rozek, A., Sierks, H., A'Hearn, M. F., Angrilli, F., Barbieri, C., Barucci, M. A., Bertaux, J-L, Cremonese, G., Da Deppo, V., Davidsson, Björn, De Cecco, M., Debei, S., Fornasier, S., Fulle, M., Groussin, O., Gutierrez, P., Hviid, S. F., Ip, W., Jorda, L., Keller, H. U., Knollenberg, J., Koschny, D., Kramm, R., Kuehrt, E., Kueppers, M., Lara, L., Lazzarin, M., Lopez Moreno, J. J., Marzari, F., Michalik, H., Naletto, G., Rickman, Hans, Rodrigo, R., Sabau, L., Thomas, N., Wenzel, K-P, Agarwal, J., Bertini, I., Ferri, F., Guettler, C., Magrin, S., Oklay, N., Tubiana, C., Vincent, J-B, Mottola, S., Lowry, S., Snodgrass, C., Lamy, P. L., Toth, I., Rozek, A., Sierks, H., A'Hearn, M. F., Angrilli, F., Barbieri, C., Barucci, M. A., Bertaux, J-L, Cremonese, G., Da Deppo, V., Davidsson, Björn, De Cecco, M., Debei, S., Fornasier, S., Fulle, M., Groussin, O., Gutierrez, P., Hviid, S. F., Ip, W., Jorda, L., Keller, H. U., Knollenberg, J., Koschny, D., Kramm, R., Kuehrt, E., Kueppers, M., Lara, L., Lazzarin, M., Lopez Moreno, J. J., Marzari, F., Michalik, H., Naletto, G., Rickman, Hans, Rodrigo, R., Sabau, L., Thomas, N., Wenzel, K-P, Agarwal, J., Bertini, I., Ferri, F., Guettler, C., Magrin, S., Oklay, N., Tubiana, C., and Vincent, J-B

Abstract

Aims. Approach observations with the Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) experiment onboard Rosetta are used to determine the rotation period, the direction of the spin axis, and the state of rotation of comet 67P's nucleus. Methods. Photometric time series of 67P have been acquired by OSIRIS since the post wake-up commissioning of the payload in March 2014. Fourier analysis and convex shape inversion methods have been applied to the Rosetta data as well to the available ground-based observations. Results. Evidence is found that the rotation rate of 67P has significantly changed near the time of its 2009 perihelion passage, probably due to sublimation-induced torque. We find that the sidereal rotation periods P-1 = 12.76129 +/- 0.00005 h and P2 = 12.4043 +/- 0.0007 h for the apparitions before and after the 2009 perihelion, respectively, provide the best fit to the observations. No signs of multiple periodicity are found in the light curves down to the noise level, which implies that the comet is presently in a simple rotation state around its axis of largest moment of inertia. We derive a prograde rotation model with spin vector J2000 ecliptic coordinates lambda = 65 degrees +/- 15 degrees, beta = + 59 degrees +/- 15 degrees, corresponding to equatorial coordinates RA = 22 degrees, Dec = +76 degrees. However, we find that the mirror solution, also prograde, at lambda = 275 degrees +/- 15 degrees, beta = + 50 degrees +/- 15 degrees (or RA = 274 degrees, Dec = +27 degrees), is also possible at the same confidence level, due to the intrinsic ambiguity of the photometric problem for observations performed close to the ecliptic plane.

Published
2014
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147. 67P/Churyumov-Gerasimenko: Activity between March and June 2014 as observed from Rosetta/OSIRIS

Author

Tubiana, C., primary, Snodgrass, C., additional, Bertini, I., additional, Mottola, S., additional, Vincent, J.-B., additional, Lara, L., additional, Fornasier, S., additional, Knollenberg, J., additional, Thomas, N., additional, Fulle, M., additional, Agarwal, J., additional, Bodewits, D., additional, Ferri, F., additional, Güttler, C., additional, Gutierrez, P. J., additional, La Forgia, F., additional, Lowry, S., additional, Magrin, S., additional, Oklay, N., additional, Pajola, M., additional, Rodrigo, R., additional, Sierks, H., additional, A’Hearn, M. F., additional, Angrilli, F., additional, Barbieri, C., additional, Barucci, M. A., additional, Bertaux, J.-L., additional, Cremonese, G., additional, Da Deppo, V., additional, Davidsson, B., additional, De Cecco, M., additional, Debei, S., additional, Groussin, O., additional, Hviid, S. F., additional, Ip, W., additional, Jorda, L., additional, Keller, H. U., additional, Koschny, D., additional, Kramm, R., additional, Kührt, E., additional, Küppers, M., additional, Lazzarin, M., additional, Lamy, P. L., additional, Lopez Moreno, J. J., additional, Marzari, F., additional, Michalik, H., additional, Naletto, G., additional, Rickman, H., additional, Sabau, L., additional, and Wenzel, K.-P., additional

Published
2014
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148. The rotation state of 67P/Churyumov-Gerasimenko from approach observations with the OSIRIS cameras on Rosetta

Author

Mottola, S., primary, Lowry, S., additional, Snodgrass, C., additional, Lamy, P. L., additional, Toth, I., additional, Rożek, A., additional, Sierks, H., additional, A’Hearn, M. F., additional, Angrilli, F., additional, Barbieri, C., additional, Barucci, M. A., additional, Bertaux, J.-L., additional, Cremonese, G., additional, Da Deppo, V., additional, Davidsson, B., additional, De Cecco, M., additional, Debei, S., additional, Fornasier, S., additional, Fulle, M., additional, Groussin, O., additional, Gutiérrez, P., additional, Hviid, S. F., additional, Ip, W., additional, Jorda, L., additional, Keller, H. U., additional, Knollenberg, J., additional, Koschny, D., additional, Kramm, R., additional, Kührt, E., additional, Küppers, M., additional, Lara, L., additional, Lazzarin, M., additional, Lopez Moreno, J. J., additional, Marzari, F., additional, Michalik, H., additional, Naletto, G., additional, Rickman, H., additional, Rodrigo, R., additional, Sabau, L., additional, Thomas, N., additional, Wenzel, K.-P., additional, Agarwal, J., additional, Bertini, I., additional, Ferri, F., additional, Güttler, C., additional, Magrin, S., additional, Oklay, N., additional, Tubiana, C., additional, and Vincent, J.-B., additional

Published
2014
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149. The geomorphology of (21) Lutetia : Results from the OSIRIS imaging system onboard ESA's Rosetta spacecraft

Author

Thomas, N., Barbieri, C., Keller, H. U., Lamy, P., Rickman, Hans, Rodrigo, R., Sierks, H., Wenzel, K. P., Cremonese, G., Jorda, L., Kueppers, M., Marchi, S., Marzari, F., Massironi, M., Preusker, F., Scholten, F., Stephan, K., Barucci, M. A., Besse, S., El-Maarry, M. R., Fornasier, S., Groussin, O., Hviid, S. F., Koschny, D., Kuehrt, E., Martellato, E., Moissl, R., Snodgrass, C., Tubiana, C., Vincent, J. -B, Thomas, N., Barbieri, C., Keller, H. U., Lamy, P., Rickman, Hans, Rodrigo, R., Sierks, H., Wenzel, K. P., Cremonese, G., Jorda, L., Kueppers, M., Marchi, S., Marzari, F., Massironi, M., Preusker, F., Scholten, F., Stephan, K., Barucci, M. A., Besse, S., El-Maarry, M. R., Fornasier, S., Groussin, O., Hviid, S. F., Koschny, D., Kuehrt, E., Martellato, E., Moissl, R., Snodgrass, C., Tubiana, C., and Vincent, J. -B

Abstract

The surface of (21) Lutetia is highly complex with significant interactions between ancient and more recent structures. This work attempts to summarize the surface geomorphology observed using the high resolution images from OSIRIS, the imaging system onboard the European Space Agency's Rosetta spacecraft. A wide range of surface morphologies are seen including heavily cratered terrain, extensive sets of lineaments, young impact craters, and a ridge, the height of which is more than 1/5th of the mean radius of the body. Very young and very old terrains (as inferred from crater densities) are seen in close proximity. The longest continuous lineament is over 80 km long. The lineaments show regional-dependent organization and structure. Several categories of lineament can be described. Lineaments radial to impact craters as seen on other asteroidal bodies are mostly absent. Although the lineaments may be of seismic origin (and possibly the result of several impact-induced events), impacts producing recent large craters place constraints on seismic phenomena. In particular, stronger attenuation of shocks than seen on other asteroidal bodies seems to be required. Inhomogeneous energy transport, possibly matching observed inhomogeneous ejecta deposition may offer explanations for some of the observed phenomena. Some impact craters show unusual forms, which are probably the result of impact into a surface with relief comparable to the resultant crater diameter and/or oblique impact. There is evidence that re-surfacing through landslides has occurred at several places on the object. (C) 2011 Elsevier Ltd. All rights reserved.

Published
2012
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150. Physical Properties of Craters on Asteroid (21) Lutetia

Author

Vincent, J. -B, Marchi, S., Besse, S., Böhnhardt, H., Sierks, H., A’Hearn, M., Angrilli, F., Barbieri, C., Barucci, A., Cremonese, G., da Deppo, V., Davidsson, Björn, Debei, S., de Cecco, M., Fornasier, S., Fulle, M., Groussin, O., Gutierrez, P., Hviid, S. F., Ip, W. -H, Keller, H. U., Kramm, J. R., Knollenberg, J., Koschny, D., Kuehrt, E., Kueppers, M., Lamy, P., Lara, L. M., Lazzarin, M., Lopez-Moreno, J. J., Magrin, S., Marzari, F., Massironi, M., Michalik, H., Naletto, G., Rickman, H., Rodrigo, R., Sabau, L., Thomas, N., Wenzel, K. -P, Vincent, J. -B, Marchi, S., Besse, S., Böhnhardt, H., Sierks, H., A’Hearn, M., Angrilli, F., Barbieri, C., Barucci, A., Cremonese, G., da Deppo, V., Davidsson, Björn, Debei, S., de Cecco, M., Fornasier, S., Fulle, M., Groussin, O., Gutierrez, P., Hviid, S. F., Ip, W. -H, Keller, H. U., Kramm, J. R., Knollenberg, J., Koschny, D., Kuehrt, E., Kueppers, M., Lamy, P., Lara, L. M., Lazzarin, M., Lopez-Moreno, J. J., Magrin, S., Marzari, F., Massironi, M., Michalik, H., Naletto, G., Rickman, H., Rodrigo, R., Sabau, L., Thomas, N., and Wenzel, K. -P

Abstract

This abstract presents the physical properties of craters derived from the measurement of depth/diameter ratios on asteroid (21) Lutetia. We show how the d/D ratio varies in different regions and how it can be used to better understand the processes that affected the surface.

Published
2011

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