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1. Venus Atmospheric Dynamics at Two Altitudes: Akatsuki and Venus Express Cloud Tracking, Ground-Based Doppler Observations and Comparison with Modelling

Author: Pedro Machado, Thomas Widemann, Javier Peralta, Gabriella Gilli, Daniela Espadinha, José E. Silva, Francisco Brasil, José Ribeiro, and Ruben Gonçalves
Subjects: Venus, atmosphere, atmospheres, dynamics, spectroscopy, cloud tracking, Meteorology. Climatology, QC851-999
Abstract: We present new results of our studies of zonal and meridional winds in both hemispheres of Venus, using ground- and space-based coordinated observations. The results obtained from telescope observations were retrieved with a Doppler velocimetry method. The wind velocities retrieved from space used an improved cloud-tracked technique based on the phase correlation between images. We present evidence that the altitude level sensed by our Doppler velocimetry method is approximately four kilometres higher (~4 km) than that using ground-tracked winds (using 380 or 365 nm). Since we often take advantage of coordinated space and ground observations simultaneously, this altitude difference will be very relevant in order to estimate the vertical wind shear at the related heights in future observation campaigns. We also explored a previous coordinated campaign using Akatsuki observations and its Ultraviolet Imager (UVI) at 283 and 365 nm filters, which showed that cloud-tracked winds showed a difference of about 10–15 ms−1, as in the case of the comparison between the Doppler velocimetry winds and the 365 nm cloudtracked winds. The results’ comparison also strongly suggested that the cloud-tracked winds based on the 283 nm filter’s images were sensing at about the same atmospheric altitude level as the Doppler winds. The observational results were compared with the ground-to-thermosphere 3D model developed at the Laboratoire de Meteorologie Dynamique (IPSL-Venus General Circulation Model (VGCM)) and AFES-Venus General Circulation Model (GCM), at several pressure levels (and related heights). The analysis and results showed the following: (1) additional confirmation of the coherence and complementarity in the results provided by these techniques on both the spatial and temporal time scales of the two methods; (2) we noticed in the following that the results from the two different Akatsuki/UVI filters (283 and 365 nm) showed an average difference of about 10–15 ± 5 ms−1, and we suggest this may be related to SO2 atmospheric fluctuations and the particular conditions in the coordinated observing time window; (3) we present evidence indicating that, in the context of our observations, visible Doppler methods (highly self-consistent) seem to sense wind speeds at a vertical level closer to or within the range sensed by the UVI 283 nm filter images (again, in the context of our observations); (4) modelling predicted wind profiles suggests that the layers of the atmosphere of Venus sensed by the methods referred to in Point 3 differ by approximately four km in altitude (~4 ± 2 km) regarding the cloud-tracked winds retrieved using 365 or 380 nm images.
Published: 2021
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2. A Wind Study of Venus’s Cloud Top: New Doppler Velocimetry Observations

Author: Ruben Gonçalves, Pedro Machado, Thomas Widemann, Francisco Brasil, and José Ribeiro
Subjects: venus, atmosphere, atmosphere, dynamics, spectroscopy, doppler velocimetry, Meteorology. Climatology, QC851-999
Abstract: At Venus’s cloud top, the circulation is dominated by the superroration, where zonal wind speed peaks at ∼100 ms−1, in the low-to-middle latitudes. The constraining of zonal and meridional circulations is essential to understanding the mechanisms driving the superrotation of Venus’s atmosphere, which are still poorly understood. We present new Doppler velocimetry measurements of horizontal wind velocities at Venus’s cloud top, around 70 km altitude. These results were based on March 2015 observations at the Canada–France–Hawaii Telescope (CFHT, Mauna Kea, Hawaii), using ESPaDOnS. The Doppler velocimetry method used has already successfully provided zonal and meridional results in previous works led by P. Machado and R. Gonçalves, proving to be a good reference ground-based technique in the study of the dynamics of Venus’s atmosphere. These observations were carried out between 27 and 29 March 2015, using the Echelle SpectroPolarimetric Device for the Observation of Stars (ESPaDOnS) which provides simultaneous visible-near IR spectra from 370 to 1050 nm, with a spectral resolution of 81000 allowing wind field characterization in the scattered Franuhofer solar lines by Venus’s cloud top on the dayside. The zonal velocities are consistent with previous results while also showing evidence of spatial variability, along planetocentric latitude and longitude (local-time). The meridional wind circulation presents a notably constant latitudinal structure with null velocities at lower latitudes, below 10∘ N–S, and peak velocities of ∼30 ms−1, centered around 35∘ N–S. The uncertainty of the meridional wind results from ground observations is of the same order as the uncertainty of meridional wind retrieved by space-based observations using cloud-tracking, as also shown by previous work led by R. Gonçalves and published in 2020. These March 2015 measurements present a unique and valuable contribution to the study of horizontal wind at the cloud top, from a period when Doppler velocimetry was the only available method to do so, since no space mission was orbiting Venus between Venus Express ending in January 2015 and Akatsuki’s orbit insertion in December 2015. These results from new observations provide (1) constraints on zonal wind temporal and spatial variability (latitude and local time), (2) constraints on the meridional wind latitudinal profile, (3) additional evidence of zonal and meridional wind stability for the period between 2011 and 2015 (along previous Doppler results) (4) further evidence of the consistency and robustness of our Doppler velocimetry method.
Published: 2020
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3. EnVision: a Nominal Science Phase Spanning Six Venus Sidereal Days

Author: Thomas Widemann, Anne Grete Straume, Adriana Ocampo, Thomas Voirin, Lynn Carter, Scott Hensley, Lorenzo Bruzzone, Joern Helbert, Ann Carine Vandaele, Emmanuel Marcq, and Caroline Dumoulin
Abstract: EnVision was selected as ESA’s 5th M-class mission, targeting a launch in the early 2030s. The mission is a partnership between ESA and NASA, where NASA provides the Synthetic Aperture Radar payload. The scientific objective of EnVision is to provide a holistic view of the planet from its inner core to its upper atmosphere. The mission phase B1 started in December 2021 to complete trade-offs, consolidate requirements, interfaces and system specifications. Phase B1 will be concluded with the Mission Adoption Review planned in fall 2023, followed by Mission Adoption in 2024. To meet its science objectives, the EnVision mission needs to return a significant volume of science data to Earth, with a large distance-to-Earth dynamic range (from 0.3 to 1.7 AU), from a low Venus polar orbit, in the hot Venus environment (exacerbated by the operation of highly dissipative units), while operating three spectrometers in an almost cryogenic level environment. This needs to be achieved within constraints on the spacecraft mass as well as Agency programmatic boundaries. Achieving the science objectives under these multiple constraints without oversizing the spacecraft calls for a careful planning of science operations, making the science planning strategy a critical driver in the design of the whole mission, against which the spacecraft and ground segment are then sized.The payload reference operations scenario simulation demonstrates that all identified surface targets can be imaged with VenSAR, with a performance fully compliant with the science requirements. The first two cycles allow imaging once 80% of the identified Regions of Interest (RoIs) at 30 m resolution. The following two cycles are mostly devoted to 2nd observations of these areas for stereo-topography mapping and the two last cycles to 3rd observations of the “activity” type. Dual polarization and high resolution SAR observations can be performed at any longitude at least once across the 6 cycles. Our strategy is to obtain the widest range of data types that enables us to put the highest resolution datasets into regional and global context. Similarly, understanding atmospheric processes requires a combination of global-scale mapping with targeted observations resolving smaller-scale processes.
Published: 2023

4. EnVision: understanding why our closest neighbour is so different

Author: Thomas Widemann, Anne Grete Straume-Lindner, Adriana C. Ocampo, Thomas Voirin, Ann Carine Vandaele, Alberto Moreira, Bruce Campbell, Caroline Dumoulin, Emmanuel Marcq, Gabriella Gilli, Jörn Helbert, Walter Kiefer, Lynn Carter, Lorenzo Bruzzone, Philippa Mason, Scott Hensley, and Tatiana Bocanegra-Bahamon
Abstract: EnVision was selected as ESA's 5th Medium-class mission in the Agency's Cosmic Vision plan, targeting a launch in the early 2030s. EnVision's overarching science questions are to explore the full range of geoscientific processes operating on Venus. It will investigate Venus from its inner core to its atmosphere at an unprecedented scale of resolution, characterising in particular core and mantle structure, signs of past geologic processes, and looking for evidence of past liquid water. Far more than a simple radar mission, this suite of investigations works together to comprehensively assess surface and subsurface geological processes, interior geophysics and geodynamics, and atmospheric pathways of key volcanogenic gases, which together illuminate how and why Venus turned out so differently to Earth. Recent modeling studies strongly suggest that the evolution of the atmosphere and interior of Venus are coupled, emphasizing the need to study the atmosphere, surface, and interior of Venus as a system. EnVision is an ESA Venus orbiter mission formulated in collaboration with NASA; As a key partner in the mission, NASA provides the Synthetic Aperture Radar, VenSAR. The EnVision payload consists of five instruments provided by European and US institutions. The five instruments comprise a comprehensive measurement suite spanning infrared, ultraviolet- visible, microwave and high frequency wavelengths, complemented by the Radio Science investigation exploiting the spacecraft TT&C system. All instruments in the payload have substantial heritage and robust margins relative to the requirements with designs suitable for operation in the Venus environment. This suite of instruments was chosen to meet the broad spectrum of measurement requirements needed to support EnVision science investigations.
Published: 2022

5. Ground-based HDO and SO2 thermal mapping on Venus between 2012 and 2022: : An update

Author: Therese Encrenaz, Thomas Greathouse, Rohini Giles, Thomas Widemann, Bruno Bézard, and Thierry Fouchet
Abstract: Since 2012, we have been monitoring SO2 and H2O (using HDO as a proxy) at the cloud top of Venus, using the TEXES high-resolution imaging spectrometer at the NASA InfraRed Telescope Facility (IRTF) at Maunakea Observatory. Sixteen runs have been performed between 2012 and 2022. Maps have been recorded around 1345 cm-1 (7.4 microns, z = 62 km), where SO2, CO2 and HDO are observed, and around 530 cm-1 (19 microns, z = 57 km) where SO2 and CO2 are observed, as well as around 1162 cm-1 (8.6 microns, z = 66 km) where CO2 is observed. From the early beginning, SO2 plumes have been identified with an evolution time scale of a few hours. In 2020, an anti-correlation has been found in the long-term evolution of H2O and SO2; in addition, the SO2 plume appearance as a function of local time seems to show two maxima around the terminator, indicating the possible presence of a semi-diurnal wave (Encrenaz et al. A&A 639, A69, 2020). After two years of interruption due to the pandemia, new observations have been performed in July 2021, September 2021, November 2021, and February 2022. The main results of the new observations are listed below. (1)The SO2 abundance, which had been globally increasing from 2014 until 2019, has now decreased with respect to its maximum value. (2) The anti-correlation between H2O and SO2, which was maximum between 2014 and 2019 (cc = - 0.9) does not appear clearly in the recent observations. (3) The maximum appearance of the SO2 plumes at the equator and the terminators is confirmed, but appears stronger on the morning side.(4) A strong activity of the SO2 plumes is observed in September and November 2021, at a time when the disk-integrated SO2 abundance is low. At the same time, thermal maps at 1162 cm-1 (8.6 microns, z = 66 km) show a polar enhancement. This behavior could possibly be associated with the topography.
Published: 2022

6. The EnVision Mission to Venus

Author: Thomas Widemann, Richard Ghail, Colin Wilson, Dmitri Titov, Anne Grete Straume, Adriana Ocampo, Tatiana Bocanegra-Bahamon, Lorenzo Bruzzone, Bruce Campbell, Lynn Carter, Caroline Dumoulin, Gabriella Gilli, Jörn Helbert, Scott Hensley, Walter Kiefer, Emmanuel Marcq, Philippa Mason, Alberto Moreira, and Ann Carine Vandaele
Subjects: Spektroskopie, Mission, Venus
Abstract: On June 10, 2021, the European Space Agency (ESA) announced the selection of EnVision as its newest medium-class science mission. EnVision's overarching science questions are to explore the full range of geoscientific processes operating on Venus [1, 2]. It will investigate Venus from its inner core to its atmosphere at an unprecedented scale of resolution, characterising in particular core and mantle structure, signs of past geologic processes, and looking for evidence of past liquid water. Recent modeling studies strongly suggest that the evolution of the atmosphere and interior of Venus are coupled, emphasizing the need to study the atmosphere, surface, and interior of Venus as a system. The nominal science phase of the mission will last six Venus sidereal days (four Earth years). EnVision will downlink 210 Tbits of science data, using a Ka-/X-band comms system with a 2.5 m diameter fixed high-gain antenna. As a key partner in the mission, NASA provides the Synthetic Aperture Radar, VenSAR.The EnVision payload consists of five instruments provided by European and US institutions. The five instruments comprise a comprehensive measurement suite spanning infrared, ultraviolet-visible, microwave and high frequency wavelengths. This suite is complemented by the Radio Science investigation exploiting the spacecraft TT&C system. All instruments in the payload have substantial heritage and robust margins relative to the requirements with designs suitable for operation in the Venus environment. This suite of instruments was chosen to meet the broad spectrum of measurement requirements needed to support EnVision science investigations. Two parallel competitive industrial studies will continue in the Definition Phase B1, to complete trade-offs, consolidate requirements and interfaces, produce system specifications, support development of the science operations, calibration strategies, science products definition under the responsibility of the Future Missions Department (SCI-F) and under the authority of the EnVision Study Manager until Mission Adoption Review (MAR) scheduled in 2024. [1] ESA's EnVision Assessment Study Report: sci.esa.int/web/cosmic-vision/envision-assessment-study-report-yellow-book. [2] EnVision mission website: www.envisionvenus.eu.
Published: 2022

7. Ground-based HDO and SO2 thermal mapping on Venus : An update

Author: Therese Encrenaz, Thomas Greathouse, Rohini Giles, Thomas Widemann, Bruno Bézard, and Thierry Fouchet
Abstract: Since 2012, we have been monitoring SO2 and H2O (using HDO as a proxy) at the cloud top of Venus, using the TEXES high-resolution imaging spectrometer at the NASA InfraRed Telescope Facility (IRTF) at Maunakea Observatory. Maps have been recorded around 1345 cm-1 (7.4 microns), where SO2, CO2 and HDO are observed, and around 530 cm-1 (19 microns) where SO2 and CO2 are observed. An anti-correlation has been found in the long-term evolution of these two species and SO2 plumes have been identified with an evolution time scale of a few hours. The SO2 distribution as a function of local time seems to show two maxima around the terminator, indicating the possible presence of a semi-diurnal wave (Encrenaz et al. A&A 639, A69, 2020). After a year of interruption due to the Covid crisis, new observations have been performed in July and September 2021. They show that the SO2 abundance, which had been globally increasing from 2014 until 2019, has now decreased with respect to its maximum value. The new data will be analyzed in the context of the whole dataset.
Published: 2022

8. Observations of the (1-0) band of CO in Venus using VIRTIS-H aboard Venus Express

Author: Constança Freire, Thomas Widemann, Thérèse Encrenaz, Pedro Machado, and João Dias
Abstract: We have used infrared spectra of the dark side of Venus, recorded by the VIRTIS-H spectrometer (Drossart et al. Proc. SPIE 5543, 175, 2014) aboard Venus Express (Svedhem et al. JGR 113, E00B33, 2008), to analyze the CO (1-0) band around 4.7 µm. The resolving power of VIRTIS-H (about 1200) is sufficient to separate the individual lines of CO. We have selected two sets of spectra, the first one at mid-latitude (43°S) and the other in the polar collar (69-83°S). The CO individual lines appear in absorption in the first case, and in emission in the second case, as a consequence of a temperature inversion occurring at high latitude at the level of the upper cloud top. Synthetic models have been calculated using the Planetary Spectrum Generator (Villanueva et al. JQSRT 217, 86, 2018). Information is retrieved on the thermal vertical profile and the CO vertical distribution at both latitudes. This work illustrates the capabilities of high-resolution infrared spectroscopy for monitoring minor atmospheric species in the mesosphere of Venus, in the perspective of the EnVision mission (Helbert et al. Proc. SPIE 11128, A1112804, 2019).
Published: 2022

9. Ariel: Enabling planetary science across light-years

Author: Giovanna Tinetti, Paul Eccleston, Carole Haswell, Pierre-Olivier Lagage, Jérémy Leconte, Theresa Lüftinger, Giusi Micela, Michel Min, Göran Pilbratt, Ludovic Puig, Mark Swain, Leonardo Testi, Diego Turrini, Bart Vandenbussche, Maria Rosa Zapatero Osorio, Anna Aret, Jean-Philippe Beaulieu, Buchhave, Lars A., Martin Ferus, Matt Griffin, Manuel Guedel, Paul Hartogh, Pedro Machado, Giuseppe Malaguti, Enric Pallé, Mirek Rataj, Tom Ray, Ignasi Ribas, Robert Szabó, Jonathan Tan, Stephanie Werner, Francesco Ratti, Carsten Scharmberg, Jean-Christophe Salvignol, Nathalie Boudin, Jean-Philippe Halain, Martin Haag, Pierre-Elie Crouzet, Ralf Kohley, Kate Symonds, Florian Renk, Andrew Caldwell, Manuel Abreu, Gustavo Alonso, Jerome Amiaux, Michel Berthé, Georgia Bishop, Neil Bowles, Manuel Carmona, Deirdre Coffey, Josep Colomé, Martin Crook, Lucile Désjonqueres, Díaz, José J., Rachel Drummond, Mauro Focardi, Gómez, Jose M., Warren Holmes, Matthijs Krijger, Zsolt Kovacs, Tom Hunt, Richardo Machado, Gianluca Morgante, Marc Ollivier, Roland Ottensamer, Emanuele Pace, Teresa Pagano, Enzo Pascale, Chris Pearson, Søren Møller Pedersen, Moshe Pniel, Stéphane Roose, Giorgio Savini, Richard Stamper, Peter Szirovicza, Janos Szoke, Ian Tosh, Francesc Vilardell, Joanna Barstow, Luca Borsato, Sarah Casewell, Quentin Changeat, Benjamin Charnay, Svatopluk Civiš, Vincent Coudé du Foresto, Athena Coustenis, Nicolas Cowan, Camilla Danielski, Olivier Demangeon, Pierre Drossart, Edwards, Billy N., Gabriella Gilli, Therese Encrenaz, Csaba Kiss, Anastasia Kokori, Masahiro Ikoma, Juan Carlos Morales, Joao Mendonca, Andrea Moneti, Lorenzo Mugnai, Antonio García Muñoz, Ravit Helled, Mihkel Kama, Yamila Miguel, Nikos Nikolaou, Isabella Pagano, Olja Panic, Miriam Rengel, Hans Rickman, Marco Rocchetto, Subhajit Sarkar, Franck Selsis, Jonathan Tennyson, Angelos Tsiaras, Olivia Venot, Krisztián Vida, Waldmann, Ingo P., Sergey Yurchenko, Gyula Szabó, Rob Zellem, Ahmed Al-Refaie, Javier Perez Alvarez, Lara Anisman, Axel Arhancet, Jaume Ateca, Robin Baeyens, Barnes, John R., Taylor Bell, Serena Benatti, Katia Biazzo, Maria Błęcka, Aldo Stefano Bonomo, José Bosch, Diego Bossini, Jeremy Bourgalais, Daniele Brienza, Anna Brucalassi, Giovanni Bruno, Hamish Caines, Simon Calcutt, Tiago Campante, Rodolfo Canestrari, Nick Cann, Giada Casali, Albert Casas, Giuseppe Cassone, Christophe Cara, Ludmila Carone, Nathalie Carrasco, Paolo Chioetto, Fausto Cortecchia, Markus Czupalla, Chubb, Katy L., Angela Ciaravella, Antonio Claret, Riccardo Claudi, Claudio Codella, Maya Garcia Comas, Gianluca Cracchiolo, Patricio Cubillos, Vania Da Peppo, Leen Decin, Clemence Dejabrun, Elisa Delgado-Mena, Anna Di Giorgio, Emiliano Diolaiti, Caroline Dorn, Vanessa Doublier, Eric Doumayrou, Georgina Dransfield, Luc Dumaye, Emma Dunford, Antonio Jimenez Escobar, Vincent Van Eylen, Maria Farina, Davide Fedele, Alejandro Fernández, Benjamin Fleury, Sergio Fonte, Jean Fontignie, Luca Fossati, Bernd Funke, Camille Galy, Zoltán Garai, Andrés García, Alberto García-Rigo, Antonio Garufi, Giuseppe Germano Sacco, Paolo Giacobbe, Alejandro Gómez, Arturo Gonzalez, Francisco Gonzalez-Galindo, Davide Grassi, Caitlin Griffith, Mario Giuseppe Guarcello, Audrey Goujon, Amélie Gressier, Aleksandra Grzegorczyk, Tristan Guillot, Gloria Guilluy, Peter Hargrave, Marie-Laure Hellin, Enrique Herrero, Matt Hills, Benoit Horeau, Yuichi Ito, Niels Christian Jessen, Petr Kabath, Szilárd Kálmán, Yui Kawashima, Tadahiro Kimura, Antonín Knížek, Laura Kreidberg, Ronald Kruid, Kruijssen, Diederik J. M., Petr Kubelík, Luisa Lara, Sebastien Lebonnois, David Lee, Maxence Lefevre, Tim Lichtenberg, Daniele Locci, Matteo Lombini, Alejandro Sanchez Lopez, Andrea Lorenzani, Ryan MacDonald, Laura Magrini, Jesus Maldonado, Emmanuel Marcq, Alessandra Migliorini, Darius Modirrousta-Galian, Karan Molaverdikhani, Sergio Molinari, Paul Mollière, Vincent Moreau, Giuseppe Morello, Gilles Morinaud, Mario Morvan, Moses, Julianne I., Salima Mouzali, Nariman Nakhjiri, Luca Naponiello, Norio Narita, Valerio Nascimbeni, Athanasia Nikolaou, Vladimiro Noce, Fabrizio Oliva, Pietro Palladino, Andreas Papageorgiou, Vivien Parmentier, Giovanni Peres, Javier Pérez, Santiago Perez-Hoyos, Manuel Perger, Cesare Cecchi Pestellini, Antonino Petralia, Anne Philippon, Arianna Piccialli, Marco Pignatari, Giampaolo Piotto, Linda Podio, Gianluca Polenta, Giampaolo Preti, Theodor Pribulla, Manuel Lopez Puertas, Monica Rainer, Jean-Michel Reess, Paul Rimmer, Séverine Robert, Albert Rosich, Loic Rossi, Duncan Rust, Ayman Saleh, Nicoletta Sanna, Eugenio Schisano, Laura Schreiber, Victor Schwartz, Antonio Scippa, Bálint Seli, Sho Shibata, Caroline Simpson, Oliver Shorttle, Skaf, N., Konrad Skup, Mateusz Sobiecki, Sergio Sousa, Alessandro Sozzetti, Judit Šponer, Lukas Steiger, Paolo Tanga, Paul Tackley, Jake Taylor, Matthias Tecza, Luca Terenzi, Pascal Tremblin, Andrea Tozzi, Amaury Triaud, Loïc Trompet, Shang-Min Tsai, Maria Tsantaki, Diana Valencia, Ann Carine Vandaele, Mathieu Van der Swaelmen, Adibekyan Vardan, Gautam Vasisht, Allona Vazan, Ciro Del Vecchio, Dave Waltham, Piotr Wawer, Thomas Widemann, Paulina Wolkenberg, Gordon Hou Yip, Yuk Yung, Mantas Zilinskas, Tiziano Zingales, Paola Zuppella, University College of London [London] (UCL), Space Science and Technology Department [Didcot] (RAL Space), STFC Rutherford Appleton Laboratory (RAL), Science and Technology Facilities Council (STFC)-Science and Technology Facilities Council (STFC), Université de Bordeaux (UB), Agence Spatiale Européenne = European Space Agency (ESA), SRON Netherlands Institute for Space Research (SRON), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Bologna (OABO), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), 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), Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-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), 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-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Belgian Institute for Space Aeronomy / Institut d'Aéronomie Spatiale de Belgique (BIRA-IASB), European Space Agency, Agence Spatiale Européenne (ESA), European Space Agency (ESA), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Giovanna Tinetti, Paul Eccleston, Carole Haswell, Pierre-Olivier Lagage, Jérémy Leconte, Theresa Lüftinger, Giusi Micela, Michel Min, Göran Pilbratt, Ludovic Puig, Mark Swain, Leonardo Testi, Diego Turrini, Bart Vandenbussche, Maria Rosa Zapatero Osorio, Anna Aret, Jean-Philippe Beaulieu, Lars Buchhave, Martin Feru, Matt Griffin, Manuel Guedel, Paul Hartogh, Pedro Machado, Giuseppe Malaguti, Enric Pallé, Mirek Rataj, Tom Ray, Ignasi Riba, Robert Szabó, Jonathan Tan, Stephanie Werner, Francesco Ratti, Carsten Scharmberg, Jean-Christophe Salvignol, Nathalie Boudin, Jean-Philippe Halain, Martin Haag, Pierre-Elie Crouzet, Ralf Kohley, Kate Symond, Florian Renk, Andrew Caldwell, Manuel Abreu, Gustavo Alonso, Jerome Amiaux, Michel Berthé, Georgia Bishop, Neil Bowle, Manuel Carmona, Deirdre Coffey, Josep Colomé, Martin Crook, Lucile Désjonquere, José J. Díaz, Rachel Drummond, Mauro Focardi, Jose M. Gómez, Warren Holme, Matthijs Krijger, Zsolt Kovac, Tom Hunt, Richardo Machado, Gianluca Morgante, Marc Ollivier, Roland Ottensamer, Emanuele Pace, Teresa Pagano, Enzo Pascale, Chris Pearson, Søren Møller Pedersen, Moshe Pniel, Stéphane Roose, Giorgio Savini, Richard Stamper, Peter Szirovicza, Janos Szoke, Ian Tosh, Francesc Vilardell, Joanna Barstow, Luca Borsato, Sarah Casewell, Quentin Changeat, Benjamin Charnay, Svatopluk Civiš, Vincent Coudé du Foresto, Athena Cousteni, Nicolas Cowan, Camilla Danielski, Olivier Demangeon, Pierre Drossart, Billy N. Edward, Gabriella Gilli, Therese Encrenaz, Csaba Ki, Anastasia Kokori, Masahiro Ikoma, Juan Carlos Morale, João Mendonça, Andrea Moneti, Lorenzo Mugnai, Antonio García Muñoz, Ravit Helled, Mihkel Kama, Yamila Miguel, Nikos Nikolaou, Isabella Pagano, Olja Panic, Miriam Rengel, Hans Rickman, Marco Rocchetto, Subhajit Sarkar, Franck Selsi, Jonathan Tennyson, Angelos Tsiara, Olivia Venot, Krisztián Vida, Ingo P. Waldmann, Sergey Yurchenko, Gyula Szabó, Rob Zellem, Ahmed Al-Refaie, Javier Perez Alvarez, Lara Anisman, Axel Arhancet, Jaume Ateca, Robin Baeyen, John R. Barne, Taylor Bell, Serena Benatti, Katia Biazzo, Maria Błęcka, Aldo Stefano Bonomo, José Bosch, Diego Bossini, Jeremy Bourgalai, Daniele Brienza, Anna Brucalassi, Giovanni Bruno, Hamish Caine, Simon Calcutt, Tiago Campante, Rodolfo Canestrari, Nick Cann, Giada Casali, Albert Casa, Giuseppe Cassone, Christophe Cara, Ludmila Carone, Nathalie Carrasco, Paolo Chioetto, Fausto Cortecchia, Markus Czupalla, Katy L. Chubb, Angela Ciaravella, Antonio Claret, Riccardo Claudi, Claudio Codella, Maya Garcia Coma, Gianluca Cracchiolo, Patricio Cubillo, Vania Da Peppo, Leen Decin, Clemence Dejabrun, Elisa Delgado-Mena, Anna Di Giorgio, Emiliano Diolaiti, Caroline Dorn, Vanessa Doublier, Eric Doumayrou, Georgina Dransfield, Luc Dumaye, Emma Dunford, Antonio Jimenez Escobar, Vincent Van Eylen, Maria Farina, Davide Fedele, Alejandro Fernández, Benjamin Fleury, Sergio Fonte, Jean Fontignie, Luca Fossati, Bernd Funke, Camille Galy, Zoltán Garai, Andrés García, Alberto García-Rigo, Antonio Garufi, Giuseppe Germano Sacco, Paolo Giacobbe, Alejandro Gómez, Arturo Gonzalez, Francisco Gonzalez-Galindo, Davide Grassi, Caitlin Griffith, Mario Giuseppe Guarcello, Audrey Goujon, Amélie Gressier, Aleksandra Grzegorczyk, Tristan Guillot, Gloria Guilluy, Peter Hargrave, Marie-Laure Hellin, Enrique Herrero, Matt Hill, Benoit Horeau, Yuichi Ito, Niels Christian Jessen, Petr Kabath, Szilárd Kálmán, Yui Kawashima, Tadahiro Kimura, Antonín Knížek, Laura Kreidberg, Ronald Kruid, Diederik J. M. Kruijssen, Petr Kubelík, Luisa Lara, Sebastien Lebonnoi, David Lee, Maxence Lefevre, Tim Lichtenberg, Daniele Locci, Matteo Lombini, Alejandro Sanchez Lopez, Andrea Lorenzani, Ryan MacDonald, Laura Magrini, Jesus Maldonado, Emmanuel Marcq, Alessandra Migliorini, Darius Modirrousta-Galian, Karan Molaverdikhani, Sergio Molinari, Paul Mollière, Vincent Moreau, Giuseppe Morello, Gilles Morinaud, Mario Morvan, Julianne I. Mose, Salima Mouzali, Nariman Nakhjiri, Luca Naponiello, Norio Narita, Valerio Nascimbeni, Athanasia Nikolaou, Vladimiro Noce, Fabrizio Oliva, Pietro Palladino, Andreas Papageorgiou, Vivien Parmentier, Giovanni Pere, Javier Pérez, Santiago Perez-Hoyo, Manuel Perger, Cesare Cecchi Pestellini, Antonino Petralia, Anne Philippon, Arianna Piccialli, Marco Pignatari, Giampaolo Piotto, Linda Podio, Gianluca Polenta, Giampaolo Preti, Theodor Pribulla, Manuel Lopez Puerta, Monica Rainer, Jean-Michel Ree, Paul Rimmer, Séverine Robert, Albert Rosich, Loic Rossi, Duncan Rust, Ayman Saleh, Nicoletta Sanna, Eugenio Schisano, Laura Schreiber, Victor Schwartz, Antonio Scippa, Bálint Seli, Sho Shibata, Caroline Simpson, Oliver Shorttle, N. Skaf, Konrad Skup, Mateusz Sobiecki, Sergio Sousa, Alessandro Sozzetti, Judit Šponer, Lukas Steiger, Paolo Tanga, Paul Tackley, Jake Taylor, Matthias Tecza, Luca Terenzi, Pascal Tremblin, Andrea Tozzi, Amaury Triaud, Loïc Trompet, Shang-Min Tsai, Maria Tsantaki, Diana Valencia, Ann Carine Vandaele, Mathieu Van der Swaelmen, Adibekyan Vardan, Gautam Vasisht, Allona Vazan, Ciro Del Vecchio, Dave Waltham, Piotr Wawer, Thomas Widemann, Paulina Wolkenberg, Gordon Hou Yip, Yuk Yung, Mantas Zilinska, Tiziano Zingale, Paola Zuppella, 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), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), 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), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), and Cardon, Catherine
Subjects: [SDU] Sciences of the Universe [physics], Earth and Planetary Astrophysics (astro-ph.EP), [SDU.ASTR.IM] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Settore FIS/05 - Astronomia E Astrofisica, [SDU]Sciences of the Universe [physics], [SDU.ASTR.EP]Sciences of the Universe [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 - Instrumentation and Methods for Astrophysic, Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Astrophysics - Earth and Planetary Astrophysics, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM]
Abstract: Ariel, the Atmospheric Remote-sensing Infrared Exoplanet Large-survey, was adopted as the fourth medium-class mission in ESA's Cosmic Vision programme to be launched in 2029. During its 4-year mission, Ariel will study what exoplanets are made of, how they formed and how they evolve, by surveying a diverse sample of about 1000 extrasolar planets, simultaneously in visible and infrared wavelengths. It is the first mission dedicated to measuring the chemical composition and thermal structures of hundreds of transiting exoplanets, enabling planetary science far beyond the boundaries of the Solar System. The payload consists of an off-axis Cassegrain telescope (primary mirror 1100 mm x 730 mm ellipse) and two separate instruments (FGS and AIRS) covering simultaneously 0.5-7.8 micron spectral range. The satellite is best placed into an L2 orbit to maximise the thermal stability and the field of regard. The payload module is passively cooled via a series of V-Groove radiators; the detectors for the AIRS are the only items that require active cooling via an active Ne JT cooler. The Ariel payload is developed by a consortium of more than 50 institutes from 16 ESA countries, which include the UK, France, Italy, Belgium, Poland, Spain, Austria, Denmark, Ireland, Portugal, Czech Republic, Hungary, the Netherlands, Sweden, Norway, Estonia, and a NASA contribution., Comment: Ariel Definition Study Report, 147 pages. Reviewed by ESA Science Advisory Structure in November 2020. Original document available at: https://www.cosmos.esa.int/documents/1783156/3267291/Ariel_RedBook_Nov2020.pdf/
Published: 2021
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10. Venus Dynamics on the framework of Bepicolombo flyby to Venus and Akatsuki UVI coordinated observations with TNG HARPS-N observations

Author: Daniela Espadinha, Pedro Machado, Thomas Widemann, Javier Peralta, José Silva, and Francisco Brasil
Abstract: IntroductionOne of the most crucial bases and tools in planetary sciences is the general circulation model of a planet’s atmosphere. These models come as a result of the analysis of great amounts of observations, in order to accurately describe the atmospheric circulation of a planet. For Venus, the better understanding of cloud circulation can yield important results such as the possibility to explain and describe one of its most fascinating characteristics: the superrotation of Venus’ atmosphere.Methods and ToolsThe cloud-tracking method consists of an analysis of a pair of navigated and processed images, provided that we know the time interval between both. It is possible to probe the motion of cloud features between the initial and second image, either by matching specific points or areas in both images. This matching process allows us to measure displacements and velocities of cloud features and deduct the average velocity for a certain cloud layer of the atmosphere, selected in the wavelength range of the observations (Peralta et al. 2018).The use of an evolved tool of cloud tracking based on phase correlation between images and other softwares (Hueso et al. 2010) allows to explore Venus' atmospheric dynamics based on coordinated space and ground observations including Akatsuki UVI instrument, TNG/HARPS-N, and data from BepiColombo’s first Venus' flyby. Images used were navigated and processed for optimal identification of cloud features which help with the matching processes described above.The main goal of this work was to build wind profiles in different wavelengths which allow us to analyse several layers of the Venusian atmosphere. We present some results of this study following the works of Sánchez-Lavega et al. 2008, Hueso et al. 2013 and Horinouchi et al. 2018 and compare them with ground-based Doppler measurements (Machado et al. 2021).The Doppler velocimetry method mentioned in this work was initially developed by Thomas Widemann (Widemann et al., 2008) and further evolved by Pedro Machado for both long slit and fibre-fed spectrographs, using UVES/VLT and ESPaDOnS/CFHT respectively (Machado et al., 2012, 2014). This technique is based on solar light scattered on Venus’ dayside to provide instantaneous wind velocities measurements of its atmosphere. The sunlight is absorbed by cloud particles in Venus’ top clouds and then re-emitted in Earth’s direction in a single back-scatter approximation (Machado et al., 2012, 2014, 2017). Another goal of this study is connected to the detection and characterisation of atmospheric gravity waves. These waves are oscillatory disturbances on an atmospheric layer in which buoyancy acts as the restoring force. They can only exist in stably stratified atmospheres, that is, a fluid in which density varies mostly vertically (Silva et al. 2021).ResultsWith this work we present new results of studies of zonal and meridional winds in both Venus’ hemispheres, using ground- and space-based coordinated observations. The wind velocities retrieved from space used an improved cloud-tracked technique and the results obtained from telescope observations were retrieved with a Doppler velocimetry method, both already described in “Methods and Tools”. There is evidence that the altitude level sensed by the Doppler velocimetry method is approximately four kilometres higher than that using ground-tracked winds which is shown by models which predict wind profiles developed at the Laboratoire de Meteorologie Dynamique (Machado et al. 2021). References[1] Hueso et al., The Planetary Laboratory for Image Analysis (PLIA). Advances in Space Research, 46(9):1120–1138, 2010. [2] Sánchez-Lavega et al., Variable winds on Venus mapped in three dimensions. Geophysical Research Letters, 35 (13), 2008[3] Hueso et al., Venus winds from ultraviolet, visible and near infrared images from the VIRTIS instrument on Venus Express. 2013.[4] Horinouchi et al., Mean winds at the cloud top of venus obtained from two-wavelength UV imaging by Akatsuki. Earth, Planets and Space, 70:10, 2018.[7] Machado et al., Characterizing the atmospheric dynamics of Venus from ground-based Doppler velocimetry, Icarus, Volume 221, p.248-261, 2012.[6] Machado et al., Wind circulation regimes at Venus’ cloud tops: Ground-based Doppler velocimetry using CFHT/ESPaDOnS and comparison with simultaneous cloud tracking measurements using VEx/VIRTIS in February 2011, Icarus, 2014.[7] Machado et al., Venus Atmospheric Dynamics at Two Altitudes: Akatsuki and Venus Express Cloud Tracking, Ground-Based Doppler Observations and Comparison with Modelling. Atmosphere 2021, 12, 506.[8] Machadoet al., Venus cloud-tracked and Doppler velocimetry winds from CFHT/ESPaDOnS and Venus Express/VIRTIS in April 2014. Icarus, vol. 285, p. 8-26, 2017.[9] Peralta et al., Nightside Winds at the Lower Clouds of Venus with Akatsuki/IR2: Longitudinal, Local Time, and Decadal Variations from Comparison with Previous Measurements. The American Astronomical Society. The Astrophysical Journal Supplement Series, Volume 239, Number 2, 2018[10] Widemann et al., Venus Doppler winds at cloud tops observed with ESPaDOnS at CFHT, Planetary and Space Science, Volume 56, p. 1320-1334, 2008.[11] Silva et al., Characterising atmospheric gravity waves on the nightside lower clouds of Venus: a systematic analysis, A&A 649 A34, 2021. AcknowledgementsWe thank the JAXA’s Akatsuki team for support with coordinated observations. We gratefully acknowledge the collaboration of the TNG staff at La Palma (Canary Islands, Spain) - the observations were made with the Italian Telescopio Nazionale Galileo (TNG) operated on the island of La Palma by the Fundación Galileo Galilei of the INAF (Istituto Nazionale di Astrofisica) at the Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias. We acknowledge support from the Portuguese Fundação Para a Ciência e a Tecnologia (ref. PTDC/FIS-AST/29942/2017) through national funds and by FEDER through COMPETE 2020 (ref. POCI-01-0145 FEDER-007672) and through a grant of reference 2020.06389.BD.
Published: 2021

11. EnVision: Understanding why Earth's closest neighbour is so different

Author: Colin J. N. Wilson, Dmitri Titov, Thomas Widemann, and Richard Ghail
Subjects: Earth (chemistry), Geology, Astrobiology
Abstract: EnVision is a proposed orbiter mission aiming at determining the nature and current state of Venus' geological evolution and its relationship with the atmosphere, to understand how and why Venus and Earth evolved so differently. It is is one of two M5 mission concepts in Phase A study with a final down-selection expected in June 2021. EnVision’s overall science goals are- to characterise the sequence of events that generated the regional and global surface features of Venus, and characterize the geodynamics framework that controls the release of internal heat over Venus history; - to search for ongoing geological processes and determine whether the planet is active in the present era;- to characterise regional and local geological units, to better assess whether Venus once had condensed liquid water on its surface and was thus perhaps hospitable for life in its early history.EnVision will deliver new insights into geological history through complementary imagery, polarimetry, radiometry and spectroscopy of the surface coupled with subsurface sounding and gravity mapping; it will search for thermal, morphological, and gaseous signs of volcanic and other geological activity; and it will trace the fate of key volatile species from their sources and sinks at the surface through the clouds up to the mesosphere.EnVision’s science payload consists of VenSAR, a dual polarization S-band radar also operating as microwave radiometer, three spectrometers VenSpec-M, VenSpec-U and VenSpec-H designed to observe the surface and atmosphere of Venus, and the Subsurface Radar Sounder (SRS), a High Frequency (HF) sounding radar to probe the subsurface. These are complemented by a radio science investigation which achieves gravity mapping and radio occultation of the atmosphere, for a comprehensive investigation of the Venusian surface, interior and atmosphere and their interactions.
Published: 2021

12. Venus: key to understanding the evolution of terrestrial planets

Author: Thomas Widemann, R. C. Ghail, and Colin Wilson
Subjects: 010504 meteorology & atmospheric sciences, Planetary habitability, biology, Astronomy and Astrophysics, Venus, Mars Exploration Program, biology.organism_classification, 01 natural sciences, Observations and explorations of Venus, Exoplanet, Astrobiology, law.invention, Orbiter, Space and Planetary Science, law, Planet, 0103 physical sciences, Terrestrial planet, 010303 astronomy & astrophysics, Geology, 0105 earth and related environmental sciences
Abstract: In this paper, originally submitted in answer to ESA’s “Voyage 2050” call to shape the agency’s space science missions in the 2035–2050 timeframe, we emphasize the importance of a Venus exploration programme for the wider goal of understanding the diversity and evolution of habitable planets. Comparing the interior, surface, and atmosphere evolution of Earth, Mars, and Venus is essential to understanding what processes determined habitability of our own planet and Earth-like planets everywhere. This is particularly true in an era where we expect thousands, and then millions, of terrestrial exoplanets to be discovered. Earth and Mars have already dedicated exploration programmes, but our understanding of Venus, particularly of its geology and its history, lags behind. Multiple exploration vehicles will be needed to characterize Venus’ richly varied interior, surface, atmosphere and magnetosphere environments. Between now and 2050 we recommend that ESA launch at least two M-class missions to Venus (in order of priority): a geophysics-focussed orbiter (the currently proposed M5 EnVision orbiter – [1] – or equivalent); and an in situ atmospheric mission (such as the M3 EVE balloon mission – [2]). An in situ and orbital mission could be combined in a single L-class mission, as was argued in responses to the call for L2/L3 themes [3–5]. After these two missions, further priorities include a surface lander demonstrating the high-temperature technologies needed for extended surface missions; and/or a further orbiter with follow-up high-resolution surface radar imaging, and atmospheric and/or ionospheric investigations.
Published: 2021

13. The Need for Ground-Based Observations of Venus

Author: Thomas Navarro, Glenn S. Orton, Javier Peralta, Emilie Royer, Thomas Widemann, Brad J. Sandor, Yeon Joo Lee, Kevin McGouldrick, Candace Gray, Emmanuel Marcq, Arnaud Mahieux, Toru Kouyama, Kunio M. Sayanagi, and Eliot F. Young
Subjects: biology, Venus, biology.organism_classification, Geology, Astrobiology
Published: 2021

14. Habitability, Geodynamics, and the Case for Venus

Author: Suzanne Smrekar, Jeff Andrews-Hanna, Doris Breuer, Paul Byrne, Debra Buczkowski, Bruce Campbell, A. Davaille, Darby Dyar, G. Di Achille, Caleb Fassett, Martha Gilmore, Robert Grimm, Jorn Helbert, Scott Hensley, Robert Herrick, Luciano Iess, Lauren Jozwiak, Tiffany Katiaria, Marco Mastrogiuseppe, Erwan Mazarico, Nils Mueller, Daniel Nunes, Joseph O'Rourke, Patrick McGovern, Maria Raguso, Joann Stock, Constantine Tsang, Thomas Widemann, Jennifer Whitten, and Howard Zebker
Subjects: Habitabilität, biology, Planetenphysik, media_common.quotation_subject, Planetare Labore, Air space, Venus, Art, biology.organism_classification, Humanities, Geodynamik, media_common
Abstract: Primary author: Suzanne Smrekar Jet Propulsion Laboratory/California Institute of Technology, Pasadena CA ; Co-authors: Jeff Andrews-Hanna (U.AZ), Doris Breuer (DLR Berlin), Paul Byrne (NCSU), Debra Buczkowski (JHU/APL), Bruce Campbell (Nat. Air Space Museum), A. Davaille (CNRS/U. Paris-Saclay), Darby Dyar (Mt. Holyoke/PSI), G. Di Achille (INAF/Astro Obs. Teramo), Caleb Fassett (Marshall), Martha Gilmore (Wesleyan), Robert Grimm (SWRI), Jorn Helbert (DLR Berlin), Scott Hensley (JPL), Robert Herrick (U. Alaska), Luciano Iess (U.Roma), Lauren Jozwiak (JHU/APL), Tiffany Katiaria (JPL), Marco Mastrogiuseppe (U. Roma), Erwan Mazarico (Goddard), Nils Mueller (DLR Berlin), Daniel Nunes (JPL), Joseph O'Rourke (ASU); Patrick McGovern (LPI), Maria Raguso (Caltech), Joann Stock (Caltech), Constantine Tsang (SwRI), Thomas Widemann (Obs. Paris), Jennifer Whitten (Tulane), Thomas Widemann (LESIA), Howard Zebker (Stanford)
Published: 2021

15. Venus' cloud top wind study: new Doppler velocimetry measurements

Author: Thomas Widemann, Pedro Luiz Oliveira de Almeida Machado, and Ruben Gonçalves
Subjects: biology, Cloud top, Venus, Laser Doppler velocimetry, biology.organism_classification, Geology, Remote sensing
Abstract: We present new measurements of zonal and meridional wind velocities at Venus cloud-tops (~70 km) based the Doppler velocimetry method. Venus is usually referred to as Earth’s twin due to its similarities, namely the mass, radius, density and bulk chemical composition. However, a retrograde and slow rotation of the planet (a day is longer than a year), a dense atmosphere with high concentration of CO2 and a dynamic circulation of high speed winds in a superrotational state are some of the characteristics make Venus a unique and very distinctive planet. The measure of both wind circulations at cloud top is essential to our understanding of the Venus’ atmospheric circulation and to constrain the dynamics that maintain the superrotational state. The study of Venus’ atmosphere can be a fundamental key in our understanding of atmospheric dynamics and evolution of any the so-called Earth-like planet, including Earth itself. The observations were carried out between 25 and 29 March 2015, at the Echelle SpectroPolarimetric Device for the Observation of Stars (ESPaDOnS) at Canada-France-Hawaii Telescope (CFHT), in Mauna Kea, Hawaii. The spectrograph provides spectra from 370 to 1050 nm, with a resolution of up to 81000. The Doppler velocimetry method used in this work was initially developed by Widemann et al. (2008) and further improved and fine-tuned by Machado et al. (2012, 2014). The technique has proven to be a reference on the retrieval of zonal and meridional wind at Venus’ cloud top, with both long slit and fibre fed spectrographs, as shown in Machado et al. (2012) (UVES/VLT), Machado et al. (2014, 2017) (ESPaDOnS/CFHT) and Gonçalves et al. (2020) (HARPS-N/TNG). A detailed description of the method can be found in Machado et al. (2014, 2017). The method uses visible Fraunhofer lines scattered by Venus’ cloud tops. The Doppler shift measured in solar light scattered on Venus dayside is the result of two instantaneous motions: (1) a motion between the Sun and Venus upper clouds particles, which scatter incoming radiation in all directions including the observer’s (this Doppler velocity is minimal near Venus sub-solar point); (2) a motion between the observer and Venus clouds, resulting from the topocentric velocity of Venus cloud particles in the observer’s frame (this effect is minimal near Venus sub-terrestrial point). The measured Doppler shift is the combined effect of these instantaneous motions. At half-phase angle (HPA), these two effects cancel out for the zonal component of the wind field, as the relative velocities of particles toward the source of incoming radiation and towards the observer cancel each other out. Along all points lying along this meridian we assume that the retrieved Doppler velocities cannot be attributed to a zonal component, thus, a non-zonal wind regime, such as meridional wind flow, should explain the Doppler shifts observed along the HPA meridian. The high precision of this method in the retrieval of meridional wind as shown to be of the same order of meridional winds from space observations (Gonçalves et al., 2020). These new results provide new insights on (1) daily and spatial variability of zonal wind, (2) meridional wind profile and variability constrain, (3) long term analysis of zonal wind, (4) consistency of Doppler velocimetry method. Aknowledges: We acknowledge support from the Portuguese Fundação Para a Ciência e a Tecnologia (ref. PD/BD/ 128019/2016 and ref. PTDC/FIS-AST/29942/2017) through national funds and by FEDER through COMPETE 2020 (ref. POCI-01-0145 FEDER-007672). References: Gonçalves R., Machado P., Widemann T., Peralta J., Watanabe S., Yamazaki A. et al., Venus’ cloud top wind study: Coordinated Akatsuki/UVI with cloud tracking and TNG/HARPS-N with Doppler velocimetry observations. Icarus, Volume 335, https://doi.org/10.1016/j.icarus.2019.113418, 1 January 2020. Machado P., Luz D., Widemann T., Lellouch E., Witasse O., Characterizing the atmospheric dynamics of Venus from ground-based Doppler velocimetry. Icarus, vol. 221, p. 248-261, 2012. Machado P., Widemann T., Luz D., Peralta J., Wind circulation regimes at Venus’ cloud tops: Ground-based Doppler velocimetry using CFHT/ESPaDOnS and comparison with simultaneous cloud tracking measurements using VEx/VIRTIS in February 2011. Icarus, vol. 243, p. 249-263, 2014. Machado P., Widemann T., Peralta J., Gonçalves R., Donati J., Luz D., Venus cloud-tracked and Doppler velocimetry winds from CFHT/ESPaDOnS and Venus Express/VIRTIS in April 2014. Icarus, vol. 285, p. 8-26, 2017. Widemann T., Lellouch E., Donati J.F., Venus Doppler winds at cloud tops observed with ESPaDOnS at CFHT. Planetary and Space Science, vol. 56, p. 1320-1334, 2008.
Published: 2020

16. The Venus Emissivity Mapper – Obtaining Global Mineralogy of Venus from Orbit on the ESA EnVision and NASA VERITAS missions to Venus

Author: Nils Müller, Jörn Helbert, Yaquelin M. Rosas-Ortiz, Mario D'Amore, Suzanne E. Smrekar, Darby Dyar, Alessandro Maturilli, Richard Ghail, Jean-Michel Reess, Thomas Widemann, G. Alemanno, Conor Ryan, David Kappel, Emmanuel Marcq, Ingo Walter, and Gabriele Arnold
Subjects: biology, Emissivity, Astronomy, Venus, Orbit (control theory), biology.organism_classification, Geology
Abstract: Introduction: The Venus Emissivity Mapper is the first flight instrument designed to focus on mapping the surface of Venus using several atmospheric windows around 1 µm. After years of development, VEM now has a mature design. An existing laboratory prototype has verified an achievable instrument SNR of well above 1000, as well as predicted error in retrieval of relative emissivity of better than 1%, assuming the availability of improved Venus topography.VEM science goals: The instrument will provide a global map of rock type from orbit, assessing iron contents and the redox state of the surface by observing the surface with six narrow band filters, ranging from 0.86 to 1.18 µm. Three additional windows allow corrections for cloud composition and variability, two measure water abundance, and three compensate for stray light. Continuous observation of Venus’ thermal emission will also place tighter constraints on current volcanic activity. Eight channels provide measurements of atmospheric water vapor abundance as well as cloud microphysics and dynamics, permitting accurate correction of atmospheric interference on the surface data.The instrument is currently part of two Phase A studies: is part of the payload of the NASA VERITAS mission as well as of the ESA EnVision mission, here as the VenSpec-M channel in the VenSpec spectrometer suite. Combining VEM with a high-resolution radar mapper will provide key insights into the divergent evolution of Venus and Earth. Flying VEM on more than one mission will enable a long timeline of monitoring for volcanic activity on Venus. Combined with the existing VenusExpress data, VEM enables detection and mapping of surface changes over decades.VEM Design: The VEM system design is a pushbroom multispectral imaging system. It leverages a proven measurement technique pioneered by VIRTIS on Venus Express (VEX). It also incorporates lessons learned from VIRTIS to achieve greatly improved sensitivity and spectral and spatial coverage:A filter array (rather than a grating) provides wavelength stability (band-center and width-scatter) ~5× more stable and maximizes signal to the focal-plane array (FPA). Spectral windows below 1µm are covered for the first time. A two-stage baffle decreases scattered light and improves sensitivity. Use of an InGaAs detector with an integrated thermal electric cooler (TEC) eliminates the need for cryogenic cooling. The design maturity, combined with a standard camera optical design, leads to low development risk.VEM prototyping: VEM has been under development for several years with significantly financial investment from DLR. Following creation of the first breadboard model in 2015 during Phase A for the NASA Discovery proposal VERITAS, a laboratory prototype (LP) of the VEM instrument has been developed. This prototype includes the development version of the VEM optics with a filter array with two active filter strips. The optics underwent a set of calibration measurements on sub-unit level at LATMOS prior to delivery to DLR. All key optical design parameters including transmission and wavelength coverage have been verified using the VEMO prototype.A first performance evaluation of the VEM prototype used two Venus analog samples heated to Venus surface temperatures. This was performed using the Venus simulations setup at the Planetary Spectroscopy Laboratory with the prototype mounted on the chamber. The retrieved emissivities match laboratory values, and uncertainty for a single unbinned exposure is VEM atmospheric correction: Methodology for retrieving surface emissivity is complex but well understood and demonstrated. To distinguish between surface and atmospheric contributions, VEM uses an updated version of the extensively tested pipeline developed to process VIRTIS data, combined with a radiative transfer model (RTM). Surface emissivity retrieval techniques were developed based on Galileo NIMS observations at 1700, 1800 and 2300 nm. VEM cloud bands occur at 1195, 1310, and 1510 nm, the first on the flank of the 1180‑nm surface windows. VEM’s cloud bands are close to surface bands, providing near-optimal correction. Only relative emissivity measurements are needed to calculate the spectral slope to meet our surface emissivity requirements. We do not have a requirement on the accuracy of the retrieved emissivity. However, we can now tie an emissivity retrieval to in situ measurements to assess accuracy. For this comparison, the Venera 9 and 10 landing sites (not observed by VIRTIS) will be observed by VEM both on EnVision and on VERITAS.VEM observes each spot on the surface multiple times. Therefore both atmospheric and instrument noise are reduced by averaging image swaths acquired at different times. Applying the updated analysis of atmospheric error for VEM parameters and taking multiple-look averaging into account, our capability for emissivity precision is better than 1.5% for all bands and better than 1% in most bands.Conclusion: VEM builds on recent advances in the laboratory analog spectroscopy at PSL at DLR. It is the first flight instrument designed to focus on mapping the surface of Venus using atmospheric windows around 1 µm. VEM has a mature design with an existing laboratory prototype that verifies an achievable instrument SNR of >1000, as well as a predicted error in the retrieval of relative emissivity of better than 1%.
Published: 2020

17. Monitoring Venus cloud top: the VenSpec-U spectrometer on board ESA EnVision

Author: Colin Wilson, Gabriel Guignan, Benjamin Lustrement, Franck Montmessin, Richard Ghail, Ann Carine Vandaele, Jörn Helbert, Bruno Bézard, Emmanuel Marcq, Jérémie Lasue, Thomas Widemann, 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), 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), 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), 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), Belgian Institute for Space Aeronomy / Institut d'Aéronomie Spatiale de Belgique (BIRA-IASB), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Department of Atmospheric, Oceanic and Planetary Physics [Oxford] (AOPP), University of Oxford [Oxford], and Royal Holloway [University of London] (RHUL)
Subjects: biology, Spectrometer, Cloud top, Planetare Labore, VenSpec, Venus, Spektroskopie, biology.organism_classification, On board, [SDU]Sciences of the Universe [physics], Environmental science, ComputingMilieux_MISCELLANEOUS, Remote sensing
Abstract: Instrument description The VenSpec-U instrument is a dual channel UV spectral imager (low and high spectral resolution channels, “LR” and “HR” hereafter), part of the VenSpec spectrometer suite on board the proposed Venus orbiter EnVision. Each channel consists of an entrance baffle, an objective composed of two lenses and a stop diaphragm, and a spectrometer composed of a slit and a toroidal holographic grating. It also includes s shortpass filter to reject the wavelengths above the higher limit of both channel bands and a zero-order trap to avoid straylight due to internal reflexions of the grating zero-order. The optical layout is presented in Figure 1. Both LR and HR slits are parallel and the optical layout is such that both channels have the same instantaneous field of view (FoV), allowing simultaneous observations and calibrations. Each slit image is then spectrally dispersed by its respective toroidal holographic grating and is formed on a shared CMOS back-side illuminated detector. Figure 1: VenSpec-U optical layout overview, with the HR and LR channels respectively on the left and on the right. The narrow-slit axis of the detector contains the spectral information, whereas the long-slit axis contains the spatial information along the 22.5° FoV of each slit. The spectra of LR and HR channels are dispersed one above the other on the focal plane. The remaining spatial direction is provided through orbital scrolling (“pushbroom” strategy). Binning on the spatial axis is performed on the detector. The detector will be controlled such that the integration time and the binning scheme is adjusted independently (and simultaneously) for each channel giving high flexibility and providing parameters for the optimisation of each acquisition. Instrument Performance the HR channel (210-240 nm) at 0.2 nm spectral resolution and spatial sampling not coarser than 36 km (12 km target) should reach a SNR of at least 100; the LR channel (190-380 nm) at 2 nm spectral resolution and spatial sampling not coarser than 6 km (3 km target) should reach a SNR of at least 200. According to our forward model based on HST-STIS [Jessup et al., 2015] and SPICAV-UV heritage [Marcq et al., 2020], this shall be sufficient to measure the targeted species (SO, SO2, UV absorber) with a relative accuracy better than 25%. These measurements shall allow to characterize variability of Venus cloud top on temporal scales ranging from hours to years and spatial scales ranging from a few kilometers to planetary scale in relation to the climate and/or present day volcanic activity of Venus. Bibliography K. L. Jessup et al., Coordinated Hubble Space Telescope and Venus Express Observations of Venus’ upper cloud deck, Icarus 258, 2015 E. Marcq et al., Climatology of SO2 and UV absorber at Venus’ cloud top from SPICAV-UV nadir dataset, Icarus 335, 2020
Published: 2020

18. The science goals of the EnVision Venus orbiter mission

Author: Walter S. Kiefer, Thomas Widemann, Bruce A. Campbell, Veronique Ansan, Caroline Dumoulin, Séverine Robert, A. C. Vandaele, Philippa J. Mason, Doris Breuer, Francesca Bovolo, Jörn Helbert, Dmitrij Titov, Pascal Rosenblatt, Goro Komatsu, Alice Le Gall, Emmanuel Marcq, Colin J. N. Wilson, Lorenzo Bruzzone, Richard Ghail, and Scott Hensley
Subjects: Orbiter, Radar, biology, law, Missionen, Venus, Spektroskopie, biology.organism_classification, Geology, law.invention, Astrobiology
Abstract: If Venus were a newly discovered exoplanet, it would be one of the most Earth-like yet identified. Its similarity in size, bulk density and cloud top temperatures give no clue to the hellish temperatures at its surface. Venus hosts an array of geological features as complex as Earth, but without its organisation, and sustains a chemically reactive atmosphere, but without life. Proposed in response to ESA’s M5 call, with enabling support from NASA, EnVision is currently in Phase A study for the next medium-class mission opportunity proceeding towards a final mission selection in summer 2021 for a launch in 2032. Here we discuss the science questions motivating the mission in more detail. Building on discoveries from Magellan, Venus Express and Akatsuki, EnVision will focus on three overarching questions: Is Venus geodynamically active? How did Venus arrive at its current state? How does the Venus climate work and how do the interior, surface and atmosphere interact? 1 – Is Venus geodynamically active? Venus should be geologically active today and its globally young surface implies extensive volcanic resurfacing, but whether this happened in episodic global events or in a continuous process of small-scale resurfacing is uncertain. Constraining the rate of volcanic and tectonic activity can reveal whether Venus occupies one of these end members, or lies somewhere on the spectrum between. Magellan radar image mosaic of a 550 km wide region of Lada Terra (47°S, 25°E) showing a system of radar-bright and dark lava flows breaching a ridge belt and ponding in a large radar-bright deposit covering 100,000 km². Ammavaru, the source caldera, lies 300 km to the west (JPL/Caltech). Understanding the tectonic regime driving resurfacing and heat loss is as important as knowing the rate of activity. The surface appears partitioned into areas of low strain bounded by narrow high strain margins. The abundance of steep slopes and landslides implies active uplift in these high strain areas, but existing data provide no constraint on the frequency of landslides or rates of tectonic movement. Are the low strain regions actively created and destroyed, like Earth’s oceanic plates, or simply mobilised locally? What is the significance of the global network of elevated rift systems and linear lowland wrinkle-ridged plains? Unique to Venus are coronae, quasi-circular volcano-tectonic features, typically 100–500 km across. Are they the surface expression of plumes, or magmatic intrusions, or subduction zones? The processes of weathering, mass wasting and aeolian transport are critical for understanding both the geological history and climatic evolution of Venus. Venus Express found anomalously high IR emissivities near suspected active volcanoes, interpreted as fresh, unweathered lava flows, but both their mineralogy and the weathering processes involved are unknown. Magellan detected several, probably impact-related, dune fields at the limit of its resolution, and found indirect evidence for globally distributed smale-scale ripples. 2 – How Did Venus Arrive at its Current State? The cratering record reveals that the Venus surface is, on average, under 1 Ga old. While some areas are likely active today, other regions, e.g. the tessera highlands, may be considerably older. Magellan data imply a variety of age relationships and long-term activity, with a non-random association between geological features and elevation, e.g. the uplands are consistently more deformed than the lowlands. Impact craters themselves show alteration to dark floors, perhaps from airfall deposits or magmatic resurfacing. Densely fractured plains (right) abutting tessera (bottom); both are embayed by younger plains (dark areas). A steep-sided volcanic dome (upper left) may be the source of the plains or unrelated to them, and older or younger than the tesserae. Magellan image at 46°N, 360°E, after Basilevsky and McGill (2007). Constraining the history is critical to understanding not only when and how resurfaced, but whether that activity has changed systematically through time. Were the plains formed in a short period by massive outpourings or by many thousands of small flows over their entire history? Or did many different mechanisms – including sedimentary processes – operate at different times and places? Globally, Venus exhibits perhaps even more tectonic deformation than Earth: what is its role in resurfacing the planet and have the regimes of tectonic deformation changed over time? How did tesserae, especially, accumulate their extraordinary degree of deformation? The interior of Venus is probably Earth-like, but not the same; its core size is poorly constrained by Magellan gravity data. These data are consistent with an organised pattern of mantle convection but lack the resolution necessary to connect it with geological-scale features. 3 - How does the Venus climate work and how do the Interior, Surface and Atmosphere Interact? How and why the atmospheres of two Earth-like planets evolved so differently is one of the many compelling reasons to study Venus, directly addressing the question of how our own world became habitable. Understanding its evolution depends on knowing the exchanges between its interior, surface and space. The lower/middle clouds of Venus as imaged by Akatsuki IR2 camera. Dark areas represent thicker clouds, which may represent volcanic plumes of ash or sulphate particulates. (JAXA/ISAS/DART/Damia Bouic) Models suggest that the clouds are maintained by a constant input of H2O and SO2, both of which vary considerably, perhaps because of volcanic emissions. Elevated D/H ratios indicate the loss of early oceans, but the ‘starting’ mantle D/H ratio is unknown. Identification of granites in the ancient highlands would support this inference, but the direct detection and characterisation of volcanic volatiles is key to inferring past climate evolution. Beyond the specific investigations outlined above, however, the most important unknown factor in determining the present day state of Venus and its atmosphere, and how it arrived at that state, is the interaction between the interior, surface and atmosphere: the whole being more than the sum of the parts. References Basilevsky and McGill (2007), Surface evolution of Venus, in Exploring Venus as a Terrestrial Planet, Geophysical Monograph Series 176, edited by L. W. Esposito, E. R. Stofan and T. E. Cravens, pp. 23-43, American Geophysical Union, Washington, DC
Published: 2020

19. HDO and SO2 thermal mapping on Venus

Author: Shigeto Watanabe, Thomas K. Greathouse, Yeon Joo Lee, Carver J. Bierson, Xi Zhang, Wencheng D. Shao, Rohini Giles, Bruno Bézard, Hideo Sagawa, Therese Encrenaz, Sébastien Lebonnois, Thierry Fouchet, Thomas Widemann, Emmanuel Marcq, Franck Lefèvre, Sushil K. Atreya, 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), Southwest Research Institute [San Antonio] (SwRI), 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), Kyoto Sangyo University, STRATO - LATMOS, 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), Planetary Science Laboratory [Ann Arbor] (PSL), University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, Zentrum für Astronomie und Astrophysik [Berlin] (ZAA), Technische Universität Berlin (TU), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Hokkaido Information University, Department of Earth and Planetary Sciences [Santa Cruz], University of California [Santa Cruz] (UCSC), University of California-University of California, and European Project: 606798,EC:FP7:SPA,FP7-SPACE-2013-1,EUROVENUS(2013)
Subjects: Physics, planets and satellites: atmospheres, 010504 meteorology & atmospheric sciences, biology, Correlation coefficient, Terminator (solar), Imaging spectrometer, Astronomy and Astrophysics, Venus, Astrophysics, biology.organism_classification, 01 natural sciences, planets and satellites: terrestrial planets, 13. Climate action, Space and Planetary Science, Local time, 0103 physical sciences, Mixing ratio, Longitude, infrared: planetary systems, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Line (formation)
Abstract: Since January 2012, we have been monitoring the behavior of sulfur dioxide and water on Venus, using the Texas Echelon Cross-Echelle Spectrograph imaging spectrometer at the NASA InfraRed Telescope Facility (IRTF, Mauna Kea Observatory). Here, we present new data recorded in February and April 2019 in the 1345 cm−1(7.4μm) spectral range, where SO2, CO2, and HDO (used as a proxy for H2O) transitions were observed. The cloud top of Venus was probed at an altitude of about 64 km. As in our previous studies, the volume mixing ratio (vmr) of SO2was estimated using the SO2/CO2line depth ratio of weak transitions; the H2O volume mixing ratio was derived from the HDO/CO2line depth ratio, assuming a D/H ratio of 200 times the Vienna standard mean ocean water. As reported in our previous analyses, the SO2mixing ratio shows strong variations with time and also over the disk, showing evidence for the formation of SO2plumes with a lifetime of a few hours; in contrast, the H2O abundance is remarkably uniform over the disk and shows moderate variations as a function of time. We have used the 2019 data in addition to our previous dataset to study the long-term variations of SO2and H2O. The data reveal a long-term anti-correlation with a correlation coefficient of −0.80; this coefficient becomes −0.90 if the analysis is restricted to the 2014–2019 time period. The statistical analysis of the SO2plumes as a function of local time confirms our previous result with a minimum around 10:00 and two maxima near the terminators. The dependence of the SO2vmr with respect to local time shows a higher abundance at the evening terminator with respect to the morning. The dependence of the SO2vmr with respect to longitude exhibits a broad maximum at 120–200° east longitudes, near the region of Aphrodite Terra. However, this trend has not been observed by other measurements and has yet to be confirmed.
Published: 2020

20. A stringent upper limit on the PH3 abundance at the cloud top of Venus

Author: Clara Sousa-Silva, T. Fouchet, Thomas K. Greathouse, Thérèse Encrenaz, Rohini Giles, Bruno Bézard, Thomas Widemann, Emmanuel Marcq, Hideo Sagawa, Jane S. Greaves, 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), Southwest Research Institute [San Antonio] (SwRI), 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), Kyoto Sangyo University, School of Physics and Astronomy [Cardiff], Cardiff University, Department of Earth, Atmospheric and Planetary Sciences [MIT, Cambridge] (EAPS), Massachusetts Institute of Technology (MIT), European Project: 606798,EC:FP7:SPA,FP7-SPACE-2013-1,EUROVENUS(2013), 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 national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Sorbonne Université (SU), 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), and 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)
Subjects: spectroscopy, 010504 meteorology & atmospheric sciences, Infrared, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Planets, Venus, Astrophysics, 01 natural sciences, Mesosphere, Atmosphere, satellites, Planet, 0103 physical sciences, Mixing ratio, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), biology, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], imaging, Astronomy and Astrophysics, biology.organism_classification, Wavelength, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], atmospheres, Millimeter, Astrophysics - Earth and Planetary Astrophysics
Abstract: Following the announcement of the detection of phosphine (PH$_3$) in the cloud deck of Venus at millimeter wavelengths, we have searched for other possible signatures of this molecule in the infrared range. Since 2012, we have been observing Venus in the thermal infrared at various wavelengths to monitor the behavior of SO$_2$ and H$_2$O at the cloud top. We have identified a spectral interval recorded in March 2015 around 950 cm$^{-1}$ where a PH$_3$ transition is present. From the absence of any feature at this frequency, we derive, on the disk-integrated spectrum, a 3-$\sigma$ upper limit of 5 ppbv for the PH$_3$ mixing ratio, assumed to be constant throughout the atmosphere. This limit is 4 times lower than the disk-integrated mixing ratio derived at millimeter wavelengths. Our result brings a strong constraint on the maximum PH$_3$ abundance at the cloud top and in the lower mesosphere of Venus., Comment: Astronomy & Astrophysics, in press
Published: 2020

21. Atmospheric circulation of Venus measured with visible imaging spectroscopy at the THEMIS observatory

Author: François-Xavier Schmider, Thomas Widemann, Arturo López Ariste, Ivan Gonçalves, B. Gelly, Patrick Gaulme, Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Department of Astronomy [Las Cruces], New Mexico State University, New Mexico Institute of Mining and Technology [New Mexico Tech] (NMT), 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), Dynamiques patrimoniales et culturelles (DYPAC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), 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), Télescope héliographique pour l'étude du magnétisme et des instabilites solaires (THEMIS), Centre National de la Recherche Scientifique (CNRS), 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), ANR-15-CE31-0014,JOVIAL,Jupiter : Oscillations en Vitesse radiale par ImAgerie multi Longitudes(2015), Centre National de la Recherche Scientifique (CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Météo France-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Météo France-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS), LESIA, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Université de Paris, 5 place Jules Janssen, 92195 Meudon, France, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), 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 Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Lagrange, and Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange, Nice, France.
Subjects: Solar System, 010504 meteorology & atmospheric sciences, Atmospheric circulation, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Venus, Zonal and meridional, Astrophysics, 01 natural sciences, Wind speed, [SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology, Planet, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), ComputingMilieux_MISCELLANEOUS, Physics::Atmospheric and Oceanic Physics, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), biology, Astronomy and Astrophysics, biology.organism_classification, Solar telescope, 13. Climate action, Space and Planetary Science, Meridional flow, [SDU]Sciences of the Universe [physics], Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract: Measuring Venus' atmospheric circulation at different altitudes is important for understanding its complex dynamics, in particular the mechanisms driving the super-rotation. Observationally, Doppler imaging spectroscopy is in principle be the most reliable way to measure wind speeds of planetary atmospheres because it directly provides the projected speed of atmospheric particles. However, high-resolution imaging-spectroscopy is challenging, especially in the visible domain, and most of the knowledge about atmospheric dynamics has been obtained with cloud-tracking technique. The objective of the present work is to measure the global properties of Venus' atmospheric dynamics at the altitude of the uppermost clouds, which is probed by reflected solar lines in the visible domain. Our results are based on high-resolution spectroscopic observations with the long slit spectrometer of the solar telescope THEMIS. We present the first instantaneous "radial-velocity snapshot" of any planet of the solar system in the visible domain, i.e., a complete RV map of the planet obtained by stacking data on less than 10% of its rotation period. From this, we measure the properties of the zonal and meridional winds, which we unambiguously detect. We identify a wind circulation pattern that significantly differs from previous knowledge about Venus. The zonal wind displays a "hot spot" structure, featuring about 200 m/s at sunrise and 70 m/s at noon in the equatorial region. Regarding meridional winds, we detect an equator-to-pole meridional flow peaking at 45 m/s at mid latitudes, i.e., which is about twice as large as what was reported so far., Comment: Accepted in A&A, 23 pages, 19 figures, 3 tables
Published: 2019

22. Lower atmosphere and pressure evolution on Pluto from ground-based stellar occultations, 1988–2016

Author: Jean Lecacheux, Michaël Gillon, Jean Manfroid, Josselin Desmars, Robert R. Howell, T. R. Marsh, G. Benedetti-Rossi, J. G. Greenhill, A. Dias-Oliveira, Ilan Manulis, G. Wortmann, K. M. Ivarsen, J.-E. Communal, S. Renner, F. Vachier, L. Tzouganatos, M. Irzyk, P. Machado, M. Harnisch, Lawrence H. Wasserman, J. Broughton, V. Lorenzi, W. H. Allen, W. Beisker, G. Murawsky, A. Magazzu, David Polishook, J. Marques Oliveira, A. R. Gomes-Junior, M. Conti, J. P. Godard, M. Lavayssière, G. Krannich, Lawrence A. Molnar, Federica B. Bianco, S. de Visscher, Leslie A. Young, Maxime Devogele, Marcelo Assafin, Alessandro Marchini, B. Kattentidt, P. Barroy, G. Dangl, A. Eberle, J. B. Haislip, K. M. Hill, Nora Morales, Andrew A. Cole, P. Enskonatus, B. Loader, Emilio Molinari, V. S. Dhillon, O. Klös, M. Ait Moulay Larbi, Bruno Sicardy, Tanguy Bertrand, Richard Querel, K. Walzel, Diane Berard, P. Lindner, J. P. Rivet, Y. Moulane, L. Di Fabrizio, Rene Duffard, D. Vérilhac, G. McKay, Raoul Behrend, Emmanuel Jehin, Fabio Salvaggio, Greg Bolt, Ricardo Gil-Hutton, J. Milner, Martin Jelínek, J. Sérot, D. Vernet, Kosmas Gazeas, F. Signoret, K. L. Bath, A. C. Gilmore, E. Lellouch, D. Herald, A. Selva, D. Lanoiselée, M. Boutet, Ph. Bendjoya, Shai Kaspi, E. Meza, John Talbot, S. P. Littlefair, Alain Maury, Roberto Vieira-Martins, Marc W. Buie, F. Jabet, S. Kerr, A. Román, Thomas Widemann, C. Opitom, R. Zanmar Sanchez, P. B. Graham, E. Frappa, Catherine B. Olkin, H.-J. Bode, H. Eichler, J. De Queiroz, K. Lindner, A. P. LaCluyze, Zouhair Benkhaldoun, D. Gault, Alain Doressoundiram, François Forget, Riccardo Papini, T. Dobosz, B. E. Morgado, J. Rovira, B. Lade, Daniel E. Reichart, O. Faragó, R. Jansen, Luigi Mancini, A. Noschese, Noah Brosch, Felipe Braga-Ribas, A. Daassou, H. Pavlov, A. Carbognani, S. Todd, F. Colas, Y. El Azhari, C. Peterson, V. Tsamis, M. Bretton, J. Hattenbach, F. Ciabattari, Rodrigo Leiva, C. Veillet, A. J. Castro Tirado, Joe Pollock, R. Naves, Pablo Santos-Sanz, D. Hampf, D. Neel, J. L. Ortiz, S. Alonso, L. Abe, P. M. Kilmartin, Julio Camargo, J. M. Ohlert, D. Gloistein, K. Tigani, F. Marchis, M. Dohrmann, Richard G. French, Ronan Cunniffe, T. Janik, Tamás Tordai, E. F. Young, S. Parker, G. Bonnoli, A. Pennell, M. Kretlow, P. Sogorb, Z. Moravec, W. Rothe, C. Perelló, K. Guhl, A. B. Giles, B. Gährken, Françoise Roques, Valentin D. Ivanov, Giuseppe Leto, 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), Observatório do Valongo/UFRJ [Rio de Janeiro], Universidade Federal do Rio de Janeiro (UFRJ), Centre Hospitalier Universitaire de Nîmes (CHU Nîmes), 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), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Ludwig Maximilians University of Munich, Southwest Research Institute [Boulder] (SwRI), Observatorio Nacional [Rio de Janeiro], Universidade Estadual Paulista Júlio de Mesquita Filho = São Paulo State University (UNESP), Observatório Nacional/MCT, Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève (UNIGE), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), UZEI PRAGUE CZE, Partenaires IRSTEA, Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), National Institute of Water and Atmospheric Research [Lauder] (NIWA), European Southern Observatory [Santiago] (ESO), European Southern Observatory (ESO), Institut d'Astrophysique et de Géophysique [Liège], Université de Liège, Space Sciences, Technologies and Astrophysics Research Institute (STAR), Department of Physics and Astronomy [Boone], Appalachian State University, University of North Carolina System (UNC)-University of North Carolina System (UNC), Département d'Astrophysique (ex SAP) (DAP), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Universidad Nacional de San Juan (UNSJ), University of Sheffield [Sheffield], Kuriwa Observatory, Astronomical Association of Queensland (AAQ), Euraster, Observatoire de Dax, Cardiff School of European Studies (CSES), Cardiff University, Department of Earth, Planetary and Space Sciences [Los Angeles] (EPSS), University of California [Los Angeles] (UCLA), University of California-University of California, 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), Fundació Privada Observatori Esteve Duran, The Wise Observatory and The Raymond & Beverly Sackler School of Physics and Astronomy, Tel Aviv University [Tel Aviv], Wise Observatory and Department of geophysics and planetary sciences, Université Cadi Ayyad [Marrakech] (UCA), Stockport Observatory, Occultation Section [Wellington], Royal Astronomical Society of New Zealand, Laboratoire Hippolyte Fizeau (FIZEAU), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Observatoire de la Côte d'Azur (OCA), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), Università degli Studi di Perugia (UNIPG), Institut Pascal (IP), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-SIGMA Clermont (SIGMA Clermont)-Centre National de la Recherche Scientifique (CNRS), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Astronomical Union of Sparta [Sparta], Laboratoire de Physique de la Matière Condensée - UR UPJV 2081 (LPMC), Université de Picardie Jules Verne (UPJV), PEIRENE (PEIRENE), Institut Génomique, Environnement, Immunité, Santé, Thérapeutique (GEIST), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Obervatoire des Baronnies Provençales (OBP), Observatorio Montcabre, Institut Laue-Langevin (ILL), ILL, ITA, USA, GBR, FRA, DEU, ESP, ARG, AUS, AUT, BEL, BRA, CHL, GRC, ISR, MAR, NZL, POL, PRT, CZE, CHE, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Ludwig-Maximilians University [Munich] (LMU), Université de Genève = University of Geneva (UNIGE), Universidad Nacional de San Juan [Argentine] (UNSJ), University of California (UC)-University of California (UC), Université Nice Sophia Antipolis (1965 - 2019) (UNS), Tel Aviv University (TAU), Università degli Studi di Perugia = University of Perugia (UNIPG), Conselho Nacional de Desenvolvimento Científico e Tecnológico (Brasil), Ministerio de Economía y Competitividad (España), European Research Council, European Commission, Ministerio de Ciencia, Innovación y Universidades (España), and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Brasil)
Subjects: planets and satellites: physical evolution, 010504 meteorology & atmospheric sciences, Orbital eccentricity, Context (language use), Surface pressure, Atmospheric sciences, 7. Clean energy, 01 natural sciences, planets and satellites: terrestrial planets, Atmosphere, techniques: photometric, Altitude, Settore FIS/05 - Astronomia e Astrofisica, 0103 physical sciences, methods: observational, methods: data analysis, planets and satellites: atmospheres, observational [Methods], data analysis [Methods], 010303 astronomy & astrophysics, physical evolution [Planets and satellites], Optical depth, 0105 earth and related environmental sciences, methods: observational, methods: data analysis, planets and satellites: atmospheres, techniques: photometric, planets and satellites: physical evolution, planets and satellites: terrestrial planets, Astrophysics - Earth and Planetary Astrophysics, photometric [Techniques], Astronomy and Astrophysics, Albedo, Pluto, 13. Climate action, Space and Planetary Science, terrestrial planets [Planets and satellites], atmospheres [Planets and satellites], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Geology, Astrophysics - Earth and Planetary Astrophysics
Abstract: This article is dedicated to the memory of H.-J. Bode, J. G. Greenhill and O. Faragó for their long-standing support and participation to occultation campaigns. The work leading to these results has received funding from the European Research Council under the European Community’s H2020 2014-2020 ERC Grant Agreement n° 669416 “Lucky Star”. E.M. thanks support from Concytec-Fondecyt-PE and GA, FC-UNI for providing support during the 2012 July 18 occultation. B.S. thanks S. Para for partly supporting this research though a donation, J. P. Beaulieu for helping us accessing to the Hobart Observatory facilities and B. Warner, B. L. Gary, C. Erickson, H. Reitsema, L. Albert, P. J. Merritt, T. Hall, W. J. Romanishin, Y. J. Choi for providing data during the 2007 March 18 occultation. M.A. thanks CNPq (Grants 427700/2018-3, 310683/2017-3 and 473002/2013-2) and FAPERJ (Grant E-26/111.488/2013). J.L.O. thanks support from grant AYA2017-89637-R. P.S.S. acknowledges financial support from the European Union’s Horizon 2020 Research and Innovation Programme, under Grant Agreement no 687378, as part of the project “Small Bodies Near and Far” (SBNAF). J.L.O., R.D., P.S.S. and N.M. acknowledge financial support from the State Agency for Research of the Spanish MCIU through the “Center of Excellence Severo Ochoa” award for the Instituto de Astrofísica de Andalucía (SEV-2017-0709). F.B.R. acknowledges CNPq support process 309578/2017-5. G.B.R. thanks support from the grant CAPES-FAPERJ/PAPDRJ (E26/203.173/2016). J.I.B.C. acknowledges CNPq grant 308150/2016-3. R.V.M. thanks the grants: CNPq-304544/2017-5, 401903/2016-8, and Faperj: PAPDRJ-45/2013 and E-26/203.026/2015. B.M. thanks the CAPES/Cofecub-394/2016-05 grant and CAPES/Brazil – Finance Code 001. B.M. and A.R.G.J. were financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) – Finance Code 001. TRAPPIST-North is a project funded by the University of Liège, in collaboration with Cadi Ayyad University of Marrakech (Morocco). TRAPPIST-South is a project funded by the Belgian Fonds (National) de la Recherche Scientifique (F.R.S.-FNRS) under grant FRFC 2.5.594.09.F, with the participation of the Swiss National Science Foundation (FNS/SNSF). VSD, SPL, TRM and ULTRACAM are all supported by the STFC. K.G. acknowledges help from the team of Archenhold-Observatory, Berlin, and A.R. thanks G. Román (Granada) for help during the observation of the 2016 July 19 occultation. A.J.C.T. acknowledges support from the Spanish Ministry Project AYA2015-71718-R (including EU funds). We thank Caisey Harlingten for the repeated use of his 50 cm telescopes in San Pedro de Atacama, Chile. We thank the Italian Telescopio Nazionale Galileo (TNG), operated on the island of La Palma by the Fundación Galileo Galilei of the INAF (Istituto Nazionale di Astrofisica) at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias. L.M. acknowledges support from the Italian Minister of Instruction, University and Research (MIUR) through FFABR 2017 fund and support from the University of Rome Tor Vergata through “Mission: Sustainability 2016” fund. The Astronomical Observatory of the Autonomous Region of the Aosta Valley (OAVdA) is managed by the Fondazione Clément Fillietroz-ONLUS, which is supported by the Regional Governmentof the Aosta Valley, the Town Municipality of Nus and the “Unité des Communes valdôtaines Mont-Émilius”. The research was partially funded by a 2016 “Research and Education”s grant from Fondazione CRT. We thank D.P. Hinson for his constructive and detailed comments that helped to improve this article., Context. The tenuous nitrogen (N2) atmosphere on Pluto undergoes strong seasonal effects due to high obliquity and orbital eccentricity, and has recently (July 2015) been observed by the New Horizons spacecraft. Aims. The main goals of this study are (i) to construct a well calibrated record of the seasonal evolution of surface pressure on Pluto and (ii) to constrain the structure of the lower atmosphere using a central flash observed in 2015. Methods. Eleven stellar occultations by Pluto observed between 2002 and 2016 are used to retrieve atmospheric profiles (density, pressure, temperature) between altitude levels of ~5 and ~380 km (i.e. pressures from ~ 10 μbar to 10 nbar). Results. (i) Pressure has suffered a monotonic increase from 1988 to 2016, that is compared to a seasonal volatile transport model, from which tight constraints on a combination of albedo and emissivity of N2 ice are derived. (ii) A central flash observed on 2015 June 29 is consistent with New Horizons REX profiles, provided that (a) large diurnal temperature variations (not expected by current models) occur over Sputnik Planitia; and/or (b) hazes with tangential optical depth of ~0.3 are present at 4–7 km altitude levels; and/or (c) the nominal REX density values are overestimated by an implausibly large factor of ~20%; and/or (d) higher terrains block part of the flash in the Charon facing hemisphere., European Research Council under the European Community’s H2020 2014-2020 ERC Grant Agreement n° 669416 “Lucky Star”, Grants 427700/2018-3, 310683/2017-3 and 473002/2013-2) and FAPERJ (Grant E-26/111.488/2013), Grant AYA2017-89637-R. P.S.S. acknowledges financial support from the European Union’s Horizon 2020 Research and Innovation Programme, under Grant Agreement no 687378, as part of the project “Small Bodies Near and Far” (SBNAF), Financial support from the State Agency for Research of the Spanish MCIU through the “Center of Excellence Severo Ochoa” award for the Instituto de Astrofísica de Andalucía (SEV-2017-0709), Support process 309578/2017-5. G.B.R. thanks support from the grant CAPES-FAPERJ/PAPDRJ (E26/203.173/2016). J.I.B.C. acknowledges CNPq grant 308150/2016-3. R.V.M. thanks the grants: CNPq-304544/2017-5, 401903/2016-8, and Faperj: PAPDRJ-45/2013 and E-26/203.026/2015. B.M. thanks the CAPES/Cofecub-394/2016-05 grant and CAPES/Brazil – Finance Code 001., Grant FRFC 2.5.594.09.F, with the participation of the Swiss National Science Foundation (FNS/SNSF), Support from the Spanish Ministry Project AYA2015-71718-R (including EU funds), Support from the Italian Minister of Instruction, University and Research (MIUR) through FFABR 2017 fund and support from the University of Rome Tor Vergata through “Mission: Sustainability 2016” fund
Published: 2019

23. HDO and SO2 thermal mapping on Venus. IV. Statistical analysis of the SO2 plumes

Author: Emmanuel Marcq, T. Encrenaz, Franck Lefèvre, T. Fouchet, Yeon Joo Lee, Shigeto Watanabe, Hideo Sagawa, Thomas Widemann, Rohini Giles, Sushil K. Atreya, Thomas K. Greathouse, B. Bézard, Sébastien Lebonnois, 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), Southwest Research Institute [San Antonio] (SwRI), 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), Kyoto Sangyo University, 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), Planetary Science Laboratory [Ann Arbor] (PSL), University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, University of Tokyo [Kashiwa Campus], Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Hokkaido Information University, 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), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), 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, and École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris)
Subjects: Physics, planets and satellites: atmospheres, [PHYS]Physics [physics], Vienna Standard Mean Ocean Water, 010504 meteorology & atmospheric sciences, biology, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Equator, Imaging spectrometer, Astronomy and Astrophysics, Venus, Astrophysics, Noon, biology.organism_classification, 01 natural sciences, planets and satellites: terrestrial planets, 13. Climate action, Space and Planetary Science, Local time, 0103 physical sciences, Mixing ratio, Longitude, infrared: planetary systems, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: Since January 2012 we have been monitoring the behavior of sulfur dioxide and water on Venus, using the Texas Echelon Cross-Echelle Spectrograph (TEXES) imaging spectrometer at the NASA InfraRed Telescope Facility (IRTF, Mauna Kea Observatory). We present here the observations obtained between January 2016 and September 2018. As in the case of our previous runs, data were recorded around 1345 cm−1 (7.4 μm). The molecules SO2, CO2, and HDO (used as a proxy for H2O) were observed, and the cloudtop of Venus was probed at an altitude of about 64 km. The volume mixing ratio of SO2 was estimated using the SO2/CO2 line depth ratios of weak transitions; the H2O volume mixing ratio was derived from the HDO/CO2 line depth ratio, assuming a D/H ratio of 200 times the Vienna Standard Mean Ocean Water (VSMOW). As reported in our previous analyses, the SO2 mixing ratio shows strong variations with time and also over the disk, showing evidence of the formation of SO2 plumes with a lifetime of a few hours; in contrast, the H2O abundance is remarkably uniform over the disk and shows moderate variations as a function of time. We performed a statistical analysis of the behavior of the SO2 plumes, using all TEXES data between 2012 and 2018. They appear mostly located around the equator. Their distribution as a function of local time seems to show a depletion around noon; we do not have enough data to confirm this feature definitely. The distribution of SO2 plumes as a function of longitude shows no clear feature, apart from a possible depletion around 100E–150E and around 300E–360E. There seems to be a tendency for the H2O volume mixing ratio to decrease after 2016, and for the SO2 mixing ratio to increase after 2014. However, we see no clear anti-correlation between the SO2 and H2O abundances at the cloudtop, neither on the individual maps nor over the long term. Finally, there is a good agreement between the TEXES results and those obtained in the UV range (SPICAV/Venus Express and UVI/Akatsuki) at a slightly higher altitude. This agreement shows that SO2 observations obtained in the thermal infrared can be used to extend the local time coverage of the SO2 measurements obtained in the UV range.
Published: 2019

24. The Venus Emissivity Mapper (VEM): Obtaining global mineralogy of Venus from orbit

Author: Constantine Tsang, Dennis Wendler, Gabriel Guignan, Emmanuel Marcq, Joern Helbert, Judit Jaenchen, Gabriele Arnold, Nils Mueller, Darby Dyar, Anko Boerner, Mario D'Amore, Suzanne E. Smrekar, Ingo Walter, Alessandro Maturilli, David Kappel, Sabrina Ferrari, Thomas Widemann, DLR Institute of Planetary Research, German Aerospace Center (DLR), Mount Holyoke College, DLR Institute for Optical Sensorsystems, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), DLR Institut für Planetenforschung, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, 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, 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), 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), Università di Pavia, Southwest Research Institute [Boulder] (SwRI), Deutsches Zentrum für Luft- und Raumfahrt (DLR), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Marija Strojnik, Maureen S. Kirk (eds.), 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, 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), 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), Università degli Studi di Pavia, California Institute of Technology (CALTECH)-NASA, Imperial College London, DLR Institute of Optical Sensor Systems, and Università degli Studi di Pavia = University of Pavia (UNIPV)
Subjects: Asteroiden und Kometen, spectroscopy, Weltrauminstrumente, 010504 meteorology & atmospheric sciences, Multispectral image, Venus, 01 natural sciences, law.invention, remote sensing, Planetenphysik, law, 0103 physical sciences, Emissivity, Radar, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Remote sensing, Echtzeit-Datenprozessierung, Venus Emissivity Mapper, biology, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Near-infrared spectroscopy, Leitungsbereich PF, Global Map, biology.organism_classification, Planetary science, 13. Climate action, composition, Orbit (dynamics), Environmental science, Planetare Sensorsysteme
Abstract: The Venus Emissivity Mapper is the first flight instrument designed to focus on mapping the surface of Venus using atmospheric windows around 1 micron. After several years of development, VEM has a mature design with an existing laboratory prototype verifying an achievable instrument SNR of well above 1000, as well as predicted error in retrieval of relative emissivity of better than 1%, assuming the availability of an improved Venus topography. It will provide a global map of rock type, iron contents and redox state of the surface by observing the surface with six narrow band filters, ranging from 0.86 to 1.18 micron. Three additional windows allow corrections for cloud composition and variability, two measure water abundance, and three compensate for stray light. Continuous observation of Venus' thermal emission will also place tighter constraints on current day volcanic activity. Eight of the channels provide measurements of atmospheric water vapor abundance as well as cloud microphysics and dynamics and permit accurate correction of atmospheric interference on the surface data. Combining VEM with a high-resolution radar mapper, such as on the ESA EnVision or NASA VERITAS mission proposals, will provide key insights into the divergent evolution of Venus and Earth.
Published: 2018

25. Search for horizontal and vertical variations of CO in the day and night side lower mesosphere of Venus from CSHELL/IRTF 4.53μm observations

Author: Thérèse Encrenaz, Emmanuel Marcq, Jean-Loup Bertaux, Thomas Widemann, Emmanuel Lellouch, Mirel Birlan, 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), 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, and 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)
Subjects: Carbon Monoxide, 010504 meteorology & atmospheric sciences, biology, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Infrared Spectroscopy, Planetary Atmospheres, Astronomy and Astrophysics, Scale height, Venus, Atmospheric sciences, biology.organism_classification, 01 natural sciences, Latitude, Aerosol, Mesosphere, Atmosphere, Altitude, 13. Climate action, Space and Planetary Science, 0103 physical sciences, Mixing ratio, Environmental science, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: High-resolution ( R ~ 43 , 000 ) spectroscopic observations of both day and night sides of Venus were acquired using CSHELL at IRTF between 2202 and 2207 cm − 1 (4.53– 4.54 μ m ) during the latest maximal eastern and western elongations of Venus in two four-nights observing runs in August 2012 and November 2013. Their purpose was to investigate the effect of the recent (from 2007 onwards) decrease of sulfur dioxide (SO2) at the cloud top level on the spatial distribution of carbon monoxide (CO), since both species are involved in the mesospheric photochemical cycles. Observations of neighboring CO2 lines are fully consistent with the previously determined aerosol scale height in the 68–74 km range. We could therefore determine CO mixing ratio on both day and night sides of Venus, taking into account both scattered solar and thermal components, as well as the overlying CO dayglow on the day side. CO spatial distribution is mostly unchanged compared to previous measurements, ranging from 25 ppmv to 45 ppmv at 70 km. The scattered solar component reveals an increase in CO with increasing altitude with a scale height of ( 5 ± 0.5 ) km between 70 and 76 km. Horizontal variability is found to be weak, with a possible increase towards higher latitudes on the day side of about 10 ppmv. Yet the accuracy of our absolute values of CO mixing ratio is limited by several assumptions, and we cannot rule out that some of the variability we measure for CO could alternatively be explained by other changes occurring in the Venusian atmosphere, e.g. changes in both dT/dz and aerosol scale height.
Published: 2015

26. The Venus Emissivity Mapper concept

Author: Alessandro Maturilli, M. Darby Dyar, Gabriel Guignan, Nils Mueller, Mario D'Amore, Anko Boerner, Jörn Helbert, David Kappel, Thomas Widemann, Emmanuel Marcq, Judit Jaenchen, Suzanne E. Smrekar, Dennis Wendler, Gabriele Arnold, Sabrina Ferrari, Ingo Walter, Strojnik, Marija, Kirk, Maureen, DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), DLR Institute for Optical Sensorsystems, 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), 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), Università degli Studi di Pavia, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Deutsches Zentrum für Luft- und Raumfahrt (DLR), Department of Astronomy of the Mount Holyoke College, Mount Holyoke College, Marija Strojnik, Maureen S. Kirk (eds.), DLR Institute of Optical Sensor Systems, and Università degli Studi di Pavia = University of Pavia (UNIPV)
Subjects: Asteroiden und Kometen, spectroscopy, 010504 meteorology & atmospheric sciences, near infrared, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Venus, 01 natural sciences, law.invention, Hochgeschwindigkeitselektronik, Interference (communication), law, 0103 physical sciences, Emissivity, Circular orbit, Radar, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Remote sensing, Echtzeit-Datenprozessierung, geography, geography.geographical_feature_category, biology, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Leitungsbereich PF, Global Map, biology.organism_classification, Volcano, 13. Climate action, Planetare Sensorsysteme, Flight instruments
Abstract: International audience; The Venus Emissivity Mapper (VEM) is the first flight instrument specially designed with a sole focus on mapping the surface of Venus using the narrow atmospheric windows around 1μm. VEM will provide a global map of surface composition as well as redox state of the surface, providing a comprehensive picture of surface-atmosphere interaction on Venus. In addition, continuous observation of the thermal emission of the Venus will provide tight constraints on current day volcanic activity. These capabilities are complemented by measurements of atmospheric water vapor abundance as well as cloud microphysics and dynamic. Atmospheric data will allow for the accurate correction of atmospheric interference on the surface measurements and represent highly valuable science on their own. A mission combining VEM with a high-resolution radar mapper such as the NASA VOX or the ESA EnVision mission proposals in a low circular orbit will provide key insights in the divergent evolution of Venus.
Published: 2017

27. Venus cloud-tracked and doppler velocimetry winds from CFHT/ESPaDOnS and Venus Express/VIRTIS in April 2014

Author: P. Machado, Thomas Widemann, D. Luz, Jean-François Donati, Ruben Gonçalves, Javier Peralta, Department of Genetics [Cambridge], University of Cambridge [UK] (CAM), 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), Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency [Sagamihara] (JAXA), 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), 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), and 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)
Subjects: Atmospheres, 010504 meteorology & atmospheric sciences, Meteorology, Terminator (solar), Venus, 01 natural sciences, Atmosphere, symbols.namesake, Phase angle (astronomy), Planet, 0103 physical sciences, 010303 astronomy & astrophysics, Spectroscopy, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, [PHYS]Physics [physics], biology, Astronomy and Astrophysics, biology.organism_classification, Geodesy, Dynamics, Space and Planetary Science, Local time, Zonal flow, symbols, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Doppler effect, Geology
Abstract: Accepted: 2016-12-10, 資料番号: SA1160314000
Published: 2017

28. Mapping the thermal structure and minor species of Venus mesosphere with ALMA submillimeter observations

Author: Emmanuel Lellouch, Thierry Fouchet, Arianna Piccialli, Thomas Widemann, R. Moreno, Thérèse Encrenaz, 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, and 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)
Subjects: Physics, [PHYS]Physics [physics], 010504 meteorology & atmospheric sciences, biology, Astronomy and Astrophysics, Context (language use), Venus, Astrophysics, Atacama Large Millimeter Array, Atmospheric sciences, biology.organism_classification, 01 natural sciences, Latitude, Mesosphere, Altitude, 13. Climate action, Space and Planetary Science, Abundance (ecology), [SDU]Sciences of the Universe [physics], 0103 physical sciences, Mixing ratio, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: Context. Water vapor and sulfur compounds are key species in the photochemistry of Venus mesosphere. These species, together with mesospheric temperatures, exhibit drastic temporal variations, both on short timescales (diurnal and day-to-day) as well on long timescales, far from being understood. Aims. We targeted CO, SO, HDO and SO 2 transitions in the submillimeter range using the Atacama Large Millimeter Array (ALMA) to study their spatial and temporal variations. Methods. Four sets of observations were acquired on different dates in November 2011 during the first ALMA Early Science observation Cycle 0. Venus angular diameter was about 11′′ with an illumination factor of 92%, so that mostly the day side of the planet was mapped. Assuming a nominal CO abundance profile, we retrieved vertical temperature profiles over the entire disk as a function of latitude and local time. Temperature profiles were later used to retrieve SO, SO 2 , and H 2 O. We used HDO as a tracer for water assuming a D/H enrichment of 200 times the terrestrial value. Results. We derived 3D maps of mesospheric temperatures in the altitude range 70−105 km. SO, SO 2 , and H 2 O are characterized by a negligible abundance below ~ 85 km followed by an increase with altitude in the upper mesosphere. Disk-averaged SO abundances present a maximum mixing ratio of 15.0 ± 3.1 ppb on November 26 followed the next day by a minimum value of 9.9 ± 1.2 ppb. Due to a very low S/N, SO 2 could only be derived from the disk-averaged spectrum on the first day of observation revealing an abundance of 16.5 ± 4.6 ppb. We found a SO 2 /SO ratio of 1.5 ± 0.4. Global maps of SO reveal strong variations both with latitude and local time and from day to day with abundance ranging from 2 O disk-averages retrievals reveal a steady decrease from November 14 to 27, with the abundance varying from 3.6 ± 0.6 ppm on the first day to 2.9 ± 0.7 ppm on the last day. H 2 O maps reveal a slightly higher abundance on the evening side compared to the morning side and a strong depletion between the first and the second day of observation.
Published: 2017

29. HDO and SO 2 thermal mapping on Venus. III. Short-term and long-term variations between 2012 and 2016

Author: C. DeWitt, Thomas Widemann, Matthew J. Richter, Bruno Bézard, S. K. Atreya, Hideo Sagawa, T. Fouchet, Thomas K. Greathouse, Th. Encrenaz, 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), Southwest Research Institute [San Antonio] (SwRI), University of California [Davis] (UC Davis), University of California, Dynamiques patrimoniales et culturelles (DYPAC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Department of Atmospheric, Oceanic, and Space Sciences [Ann Arbor] (AOSS), University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, Kyoto Sangyo University, and University of California (UC)
Subjects: 010504 meteorology & atmospheric sciences, Infrared telescope, Imaging spectrometer, Venus, Astrophysics, Rotation, 01 natural sciences, planets and satellites: terrestrial planets, Altitude, 0103 physical sciences, Mixing ratio, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Line (formation), Physics, planets and satellites: atmospheres, biology, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], planets and satellites: composition, Astronomy, Astronomy and Astrophysics, biology.organism_classification, Deuterium, 13. Climate action, Space and Planetary Science, techniques: imaging spectroscopy, [SDU]Sciences of the Universe [physics]
Abstract: International audience; We present the analysis of a four-year observational campaign using the TEXES high-resolution imaging spectrometer at the NASA Infrared Telescope Facility to map sulfur dioxide and deuterated water over the disk of Venus. Data have been recorded in two spectral ranges around 1345 cm −1 (7.4 µm) and 530 cm −1 (19 µm) in order to probe the cloudtop at an altitude of about 64 km (SO 2 and HDO at 7.4 µm) and a few kilometers below (SO 2 at 19 µm). Observations took place during six runs between January 2012 and January 2016. The diameter of Venus ranged between 12 and 33 arcsec. Data were recorded with a spectral resolving power up to 80 000 and a spatial resolution of about 1 arcsec (at 7.4 µm) and 2.5 arcsec (at 19 µm). Mixing ratios were estimated from HDO/CO 2 and SO 2 /CO 2 line depth ratios, using weak neighboring transitions of comparable depths. The whole dataset demonstrates that the two molecules behave very differently to each other. The HDO maps are uniform over the disk. The disk-integrated H 2 O mixing ratio (estimated assuming a D/H of 200 VSMOW in the mesosphere of Venus) show moderate variations (by less than a factor of 2) over the four-year period. A value of 1.0−1.5 ppmv is obtained in most of the cases. The SO 2 maps, in contrast, show strong variations over the disk of Venus, by a factor as high as 5. Long-term variations of SO 2 show that the disk-integrated SO 2 mixing ratio also varies between 2012 and 2016 by a factor as high as ten, with a minimum value of 30 +/−5 ppbv on February 26, 2014 an a maximum value of 300 +/−50 ppbv on January 14, 2016. The SO 2 maps also show a strong short-term variability. It can be seen that the SO 2 maximum feature usually follows the four-day rotation of the clouds over a timescale of two hours, which corresponds to a rotation of 7.5 deg over the planetary disk, but its morphology also changes, which suggests that the lifetime of this structure is not more than a few hours.
Published: 2016

30. Albedo and atmospheric constraints of dwarf planet Makemake from a stellar occultation

Author: S. Roland, J. P. Colque, C. Colazo, Rodolfo Smiljanic, I. de la Cueva, H. J. F. Lima, Jose Luis Ortiz, Javier Licandro, Ricardo Gil-Hutton, Alain Maury, Thomas Widemann, J. Lecacheux, Nicolás Morales, R. Vieira-Martins, Sebastian Bruzzone, T. R. Marsh, Gonzalo Tancredi, D. Weaver, Pablo Santos-Sanz, François Colas, Jean Manfroid, A. Milone, E. Pimentel, Noemi Pinilla-Alonso, Marcelo Assafin, Alexandre S. Oliveira, F. Roques, Valentin D. Ivanov, Daniel Hestroffer, M. Ortiz, D. N. da Silva Neto, V. S. Dhillon, Michaël Gillon, C. Harlingten, Breno L. Giacchini, T. G. Mueller, P. J. Gutiérrez, R. Salvo, Bruno Sicardy, Julio Camargo, Eduardo Unda-Sanzana, Audrey Thirouin, Alvaro Alvarez-Candal, Felipe Braga-Ribas, P. Cacella, M.L. Alonso, A. Campo Bagatin, Leandro Kerber, F. Organero, Marcelo Emilio, Emmanuel Jehin, Rene Duffard, S. P. Littlefair, Raoul Behrend, Emmanuel Lellouch, C. Jacques, 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 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), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)
Subjects: [PHYS]Physics [physics], Physics, Solar System, Multidisciplinary, biology, 010308 nuclear & particles physics, Dwarf planet, Astronomy, Albedo, biology.organism_classification, 01 natural sciences, Occultation, Pluto, Minor-planet moon, 13. Climate action, Geometric albedo, 0103 physical sciences, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Eris
Abstract: The icy dwarf planet Makemake has projected axes of 1,430 ± 9 and 1,502 ± 45 km and a V-band geometric albedo larger than Pluto’s but smaller than Eris’s, with no global Pluto-like atmosphere. Makemake is thought to be the third-largest dwarf planet in our Solar System, a little smaller than Pluto and Eris, but until now knowledge of its size and albedo were only approximate. This paper reports the results of observations of the occultation of a faint star known as NOMAD 1181-0235723 by Makemake on 23 April 2011. The data confirm that Makemake is smaller than Pluto and Eris, with axes of 1,430±9 km and 1,502±45 km. Makemake's mean geometric albedo — the ratio of light reflected to light received — is intermediate between that of Pluto and that of Eris. All three are icy, making them among the most reflective objects in the Solar System. And the occultation light curves rule out the presence of a global Pluto-like atmosphere on Makemake, although the presence of dark terrain might imply the presence of a localized atmosphere. Pluto and Eris are icy dwarf planets with nearly identical sizes, comparable densities and similar surface compositions as revealed by spectroscopic studies1,2. Pluto possesses an atmosphere whereas Eris does not; the difference probably arises from their differing distances from the Sun, and explains their different albedos3. Makemake is another icy dwarf planet with a spectrum similar to Eris and Pluto4, and is currently at a distance to the Sun intermediate between the two. Although Makemake’s size (1,420 ± 60 km) and albedo are roughly known5,6, there has been no constraint on its density and there were expectations that it could have a Pluto-like atmosphere4,7,8. Here we report the results from a stellar occultation by Makemake on 2011 April 23. Our preferred solution that fits the occultation chords corresponds to a body with projected axes of 1,430 ± 9 km (1σ) and 1,502 ± 45 km, implying a V-band geometric albedo pV = 0.77 ± 0.03. This albedo is larger than that of Pluto, but smaller than that of Eris. The disappearances and reappearances of the star were abrupt, showing that Makemake has no global Pluto-like atmosphere at an upper limit of 4–12 nanobar (1σ) for the surface pressure, although a localized atmosphere is possible. A density of 1.7 ± 0.3 g cm−3 is inferred from the data.
Published: 2012

31. Exploration of the Outer Solar System by Stellar Occultations

Author: Alain Doressoundiram, Françoise Roques, Y. Boissel, Bruno Sicardy, Thomas Widemann, 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), Pôle Planétologie du LESIA, 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)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and 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)
Subjects: Physics, Solar System, media_common.quotation_subject, Astronomy, Astronomy and Astrophysics, Astrophysics, Occultation, Stars, Planetary science, Space and Planetary Science, Sky, Earth and Planetary Sciences (miscellaneous), Trajectory, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], media_common
Abstract: International audience; Stellar occultations are a powerful method for exploring the outer solar system, where faintness and small angular diameters prevent us from exploring in details objects like satellites, rings, or Kuiper Belt Objects. Unique kilometric spatial resolutions or better can be reached through that method. Occultations usually observe identified objects whose trajectory is known, though the occultation events might be difficult to predict. It is also possible to explore populations of small objects populations whose density in the sky plane is large enough to search for serendipitous occultations. Various instrumental methods exist for both predicted and serendipitous occultation, both needing fast photometric recordings of target stars.
Published: 2009

32. Using the transit of Venus to probe the upper planetary atmosphere

Author: Antonio Maggio, Giuseppe Piccioni, Angelo Gambino, Fabio Reale, Giuseppina Micela, Thomas Widemann, ITA, FRA, INAF - Osservatorio Astronomico di Palermo (OAPa), Istituto Nazionale di Astrofisica (INAF), 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), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Reale, F., Gambino, A., Micela, G., Maggio, A., Widemann, T., and Piccioni, G.
Subjects: FOS: Physical sciences, General Physics and Astronomy, Venus, Bioinformatics, 7. Clean energy, General Biochemistry, Genetics and Molecular Biology, Article, Atmosphere, Atmosphere of Venus, Physics and Astronomy (all), Settore FIS/05 - Astronomia E Astrofisica, Planet, Astrophysics::Solar and Stellar Astrophysics, Transit (astronomy), Earth and Planetary Astrophysics (astro-ph.EP), [PHYS]Physics [physics], Physics, Biochemistry, Genetics and Molecular Biology (all), Multidisciplinary, Secondary atmosphere, biology, Chemistry (all), Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, General Chemistry, Radius, biology.organism_classification, Exoplanet, 13. Climate action, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract: The atmosphere of a transiting planet shields the stellar radiation providing us with a powerful method to estimate its size and density. In particular, because of their high ionization energy, atoms with high atomic number (Z) absorb short-wavelength radiation in the upper atmosphere, undetectable with observations in visible light. One implication is that the planet should appear larger during a primary transit observed in high energy bands than in the optical band. The last Venus transit in 2012 offered a unique opportunity to study this effect. The transit has been monitored by solar space observations from Hinode and Solar Dynamics Observatory (SDO). We measure the radius of Venus during the transit in three different bands with subpixel accuracy: optical (4500A), UV (1600A, 1700A), Extreme UltraViolet (EUV, 171-335A) and soft X-rays (about 10A). We find that, while the Venus optical radius is about 80 km larger than the solid body radius (the expected opacity mainly due to clouds and haze), the radius increases further by more than 70 km in the EUV and soft X-rays. These measurements mark the densest ion layers of Venus' ionosphere, providing information about the column density of CO2 and CO. They are useful for planning missions in situ to estimate the dynamical pressure from the environment, and can be employed as a benchmark case for observations with future missions, such as the ESA Athena, which will be sensitive enough to detect transits of exoplanets in high-energy bands., 13 pages, 2 figures; published in Nature Communications; the full and copy-edited version is open access at http://www.nature.com/ncomms/2015/150623/ncomms8563/full/ncomms8563.html
Published: 2015

33. Wind circulation regimes at Venus’ cloud tops: Ground-based Doppler velocimetry using CFHT/ESPaDOnS and comparison with simultaneous cloud tracking measurements using VEx/VIRTIS in February 2011

Author: David Luz, P. Machado, Thomas Widemann, Javier Peralta, Department of Rheumatology (LEIDEN - Rhumato), Leiden University Medical Center (LUMC), 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), Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency [Sagamihara] (JAXA), and Universiteit Leiden-Universiteit Leiden
Subjects: Physics, [PHYS]Physics [physics], biology, Cloud top, Astronomy, Astronomy and Astrophysics, Zonal and meridional, Venus, biology.organism_classification, Fraunhofer lines, Atmosphere of Venus, symbols.namesake, 13. Climate action, Space and Planetary Science, Meridional flow, Planet, symbols, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Doppler effect, ComputingMilieux_MISCELLANEOUS
Abstract: We present new results based on ground-based Doppler spectroscopic measurements, obtained with the ESPaDOnS spectrograph at Canada–France–Hawaii telescope (CFHT) and simultaneous observations of velocity fields, obtained from space by the VIRTIS-M instrument on board the Venus Express spacecraft. These measurements are based on high-resolution spectra of Fraunhofer lines in the visible to NIR range (0.37–1.05 μm) acquired on February 19–21, 2011 at a resolution of about 80,000, measuring Venus’ winds at 70 km, using incoming solar radiation scattered by cloud top particles in the observer’s direction (Widemann, T., et al., [2007]. Planet. Space Sci. 55, 1741–1756; Widemann, T., et al., [2008]. Planet. Space Sci. 56, 1320–1334). The zonal wind field has been characterized by latitudinal bands, at a phase angle Φ = ( 68.7 ± 0.3 ) ° , between +10°N and 60°S, by steps of 10°, and from [ ϕ - ϕ E ] = - 50 ° to sub-Earth longitude ϕ E = 0 ° , by steps of 12°. From space, VIRTIS-M UV (0.38 μm) imaging exposures on the dayside were acquired simultaneously in orbit 1786, providing the first simultaneous cloud-tracking measurements with Doppler velocimetry. From the ground, we measured a zonal mean background velocity of v ‾ z = ( 117.3 ± 18.0 ) m s - 1 on February 19, and v ‾ z = ( 117.5 ± 14.5 ) m s - 1 on February 21. We detect an unambiguous poleward meridional flow on the morning dayside hemisphere of (18.8 ± 12.3) m s−1 on February 19/21. Latitudinal variations of the zonal and meridional winds are further compared with the simultaneous VIRTIS data. We discuss temporal variability as well as its statistical significance.
Published: 2014

34. A ring system detected around the Centaur (10199) Chariklo

Author: K. M. Ivarsen, Kasper Harpsøe, Fernando Roig, N. Ligier, N. R. Frank, Rafael Sfair, Shenghong Gu, Jose Luis Ortiz, J. Lecacheux, Cyrielle Opitom, Jesper Skottfelt, J. B. Haislip, Joe Pollock, Nicolás Morales, L. Vanzi, Rodrigo Leiva, P. Lemos, François Colas, Gonzalo Tancredi, E. M. Schneiter, Frédéric Vachier, Xuefeng Wang, Marcelo Assafin, R. Vieira-Martins, R. G. Sandness, Colin Snodgrass, Nicolás Marín Martínez, Emmanuel Jehin, Marcelo Emilio, Jean Manfroid, L. Almenares, J. Spagnotto, Daniel E. Reichart, S. Roland, Martin Dominik, Thomas Widemann, U. G. Jørgensen, J. P. Moore, V. Perez, A. Ramos Gomes, C. Colazo, Markus Rabus, Pierre Kervella, D. I. Machado, Ricardo Gil-Hutton, L. Mehret, F. Roques, Julio Camargo, Bruno Sicardy, E. Lellouch, D. G. Lambas, G. Benedetti-Rossi, Alain Maury, L. Maquet, M. El Moutamid, A. Ceretta, Rene Duffard, R. Melia, Hektor Monteiro, Aaron P. LaCluyze, Michaël Gillon, F. Char, L. Lorenzini, Felipe Braga-Ribas, 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), Cátedra de Tecnología de la Madera. Departamento de Ingeniería Forestal (CTM-ETSIM), Universidad Politécnica de Madrid (UPM), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Observatorio Nacional [Rio de Janeiro], Observatório do Valongo/UFRJ [Rio de Janeiro], Universidade Federal do Rio de Janeiro (UFRJ), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Space Sciences, Technologies and Astrophysics Research Institute (STAR), Université de Liège, Department of Physics and Astronomy [Boone], Appalachian State University, University of North Carolina System (UNC)-University of North Carolina System (UNC), Southwest Research Institute [Boulder] (SwRI), Universidade Estadual de Ponta Grossa, Universidade Estadual de Ponta Grossa - State University of Ponta Grossa (UEPG), Observatorio Astronómico de Córdoba (OAC), Universidad Nacional de Córdoba [Argentina], Interactions et dynamique des environnements de surface (IDES), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatório do Valongo, Universidade Federal do Rio de Janeiro Ladeira do Pedro Antônio, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), San Pedro de Atacama Celestial Explorations (SPACE), San Pedro de Atacama Celestial Explorations, Universidad Nacional de San Juan [Argentine] (UNSJ), Instituto de Astrofisica de Canarias (IAC), Institut d'Astrophysique et de Géophysique [Liège], Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Max-Planck-Institut für Sonnensystemforschung (MPS), 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), Universidad Nacional de San Juan (UNSJ), The Royal Society, Science & Technology Facilities Council, and University of St Andrews. School of Physics and Astronomy
Subjects: RING, Solar System, 010504 meteorology & atmospheric sciences, Ciencias Físicas, Haumea, FOS: Physical sciences, Astrophysics, 01 natural sciences, 7. Clean energy, Planet, 0103 physical sciences, QB Astronomy, Trans-Neptunian object, 010303 astronomy & astrophysics, R2C, Astrophysics::Galaxy Astrophysics, ComputingMilieux_MISCELLANEOUS, QB, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, [PHYS]Physics [physics], Debris disk, Multidisciplinary, ~DC~, Astronomy, Radius, Planetary system, Galaxy, Astronomía, Astrophysics::Earth and Planetary Astrophysics, SATELLITES, BDC, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], SYSTEM, CIENCIAS NATURALES Y EXACTAS, Astrophysics - Earth and Planetary Astrophysics
Abstract: Hitherto, rings have been found exclusively around the four giant planets in the Solar System. Rings are natural laboratories in which to study dynamical processes analogous to those that take place during the formation of planetary systems and galaxies. Their presence also tells us about the origin and evolution of the body they encircle. Here we report observations of a multichord stellar occultation that revealed the presence of a ring system around (10199) Chariklo, which is a Centaur-that is, one of a class of small objects orbiting primarily between Jupiter and Neptune-with an equivalent radius of 124â â 9â kilometres (ref. 2). There are two dense rings, with respective widths of about 7 and 3 kilometres, optical depths of 0.4 and 0.06, and orbital radii of 391 and 405 kilometres. The present orientation of the ring is consistent with an edge-on geometry in 2008, which provides a simple explanation for the dimming of the Chariklo system between 1997 and 2008, and for the gradual disappearance of ice and other absorption features in its spectrum over the same period. This implies that the rings are partly composed of water ice. They may be the remnants of a debris disk, possibly confined by embedded, kilometre-sized satellites. © 2014 Macmillan Publishers Limited. Fil: Braga Ribas, F.. Observatório Nacional; Brasil Fil: Sicardy, B.. Universite Pierre et Marie Curie; Francia Fil: Ortiz, J.L.. Consejo Superior de Investigaciones Científicas; España Fil: Snodgrass, C.. Max Planck Institute for Solar System Research; Alemania Fil: Roques, F.. Universite Pierre et Marie Curie; Francia Fil: Vieira Martins, R.. Centre National de la Recherche Scientifique; Francia. Universidade Federal do Rio de Janeiro; Brasil Fil: Camargo, J.I.B.. Ministério de Ciencia, Tecnologia e Innovacao. Observatorio Nacional; Brasil Fil: Assafin, M.. Universidade Federal do Rio de Janeiro; Brasil Fil: Duffard, R.. Consejo Superior de Investigaciones Científicas; España Fil: Jehin, E.. Université de Liège; Bélgica Fil: Pollock, J.. Appalachian State University; Estados Unidos Fil: Leiva, R.. Pontificia Universidad Católica de Chile; Chile. Universidad Católica de Chile; Chile Fil: Emilio, M.. Universidade Estadual de Ponta Grossa; Brasil Fil: MacHado, D.I.. Universidade Estadual Do Oeste Do Pará; Brasil Fil: Colazo, C.. Universidad Nacional de Córdoba; Argentina. Ministerio de Educación de la Provincia de Córdoba; Argentina Fil: Lellouch, E.. Universite Pierre et Marie Curie; Francia Fil: Skottfelt, J.. University of Copenhagen; Dinamarca. Geological Museum; Dinamarca Fil: Gillon, M.. Université de Liège; Bélgica Fil: Ligier, N.. Universite Pierre et Marie Curie; Francia Fil: Maquet, L.. Universite Pierre et Marie Curie; Francia Fil: Benedetti Rossi, G.. Ministério de Ciencia, Tecnologia e Innovacao. Observatorio Nacional; Brasil Fil: Gomes, A. Ramos. Universidade Federal do Rio de Janeiro; Brasil Fil: Kervella, P.. Universite Pierre et Marie Curie; Francia Fil: Monteiro, H.. Instituto de Física e Química; Brasil Fil: Sfair, R.. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Moutamid, M. El. Universite Pierre et Marie Curie; Francia. Centre National de la Recherche Scientifique; Francia Fil: Tancredi, G.. Observatorio Astronómico Los Molinos; Uruguay. Universidad de la República; Uruguay Fil: Spagnotto, J.. Observatorio El Catalejo la Pampa; Argentina Fil: Maury, A.. San Pedro de Atacama Celestial Explorations; Chile Fil: Morales, N.. Consejo Superior de Investigaciones Científicas; España Fil: Gil Hutton, Ricardo Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Complejo Astronómico ; Argentina Fil: Roland, S.. Observatorio Astronómico Los Molinos; Uruguay Fil: Ceretta, A.. Universidad de la República; Uruguay. Observatorio del IPA; Uruguay Fil: Gu, S.-H.. Chinese Academy of Sciences; República de China Fil: Wang, X.-B.. Chinese Academy of Sciences; República de China Fil: Harpsøe, K.. University of Copenhagen; Dinamarca. Geological Museum; Dinamarca Fil: Rabus, M.. Universidad Católica de Chile; Chile. Pontificia Universidad Católica de Chile; Chile. Max Planck Institute for Astronomy; Alemania Fil: Manfroid, J.. Université de Liège; Bélgica Fil: Opitom, C.. Université de Liège; Bélgica Fil: Vanzi, L.. Pontificia Universidad Católica de Chile; Chile. Universidad Católica de Chile; Chile Fil: Mehret, L.. Universidade Estadual de Ponta Grossa; Fil: Lorenzini, L.. Polo Astronômico Casimiro Montenegro Filho; Brasil Fil: Schneiter, E.M.. Universidad Nacional de Córdoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Iate-conicet; Argentina Fil: Melia, R.. Universidad Nacional de Córdoba; Argentina Fil: Lecacheux, J.. Universite Pierre et Marie Curie; Francia Fil: Colas, F.. Centre National de la Recherche Scientifique; Francia Fil: Vachier, F.. Centre National de la Recherche Scientifique; Francia Fil: Widemann, T.. Universite Pierre et Marie Curie; Francia Fil: Almenares, L.. Universidad de la República; Uruguay. Observatorio Astronomico Los Molinos; Uruguay Fil: Sandness, R.G.. San Pedro de Atacama Celestial Explorations; Chile Fil: Char, F.. Universidad de Antofagasta; Chile Fil: Perez, V.. Universidad de la República; Uruguay. Observatorio Astronomico Los Molinos; Uruguay Fil: Lemos, P.. Universidad de la República; Uruguay. Observatorio Astronomico Los Molinos; Uruguay Fil: Martinez, N.. Universidad de la República; Uruguay. Observatorio Astronomico Los Molinos; Uruguay Fil: Jørgensen, U.G.. Universidad de Copenhagen; Dinamarca Fil: Dominik, M.. University of St. Andrews; Reino Unido Fil: Roig, F.. Ministério de Ciencia, Tecnologia e Innovacao. Observatorio Nacional; Brasil Fil: Reichart, D.E.. University of North Carolina; Estados Unidos Fil: Lacluyze, A.P.. University of North Carolina; Estados Unidos Fil: Haislip, J.B.. University of North Carolina; Estados Unidos Fil: Ivarsen, K.M.. University of North Carolina; Estados Unidos Fil: Moore, J.P.. University of North Carolina; Estados Unidos Fil: Frank, N.R.. University of North Carolina; Estados Unidos Fil: Garcia Lambas, Diego Rodolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; Argentina
Published: 2014

35. Instrumental Methods for Professional and Amateur Collaborations in Planetary Astronomy

Author: A. Leroy, Sylvain Bouley, John H. Rogers, Paolo Tanga, J. Guarro-Flo, Emmanuel Jehin, Gianluca Masi, C. Buil, Ricardo Hueso, H. B. Hammel, M. Vanhuysse, C. Pellier, A. S. Rajpurohit, P. Drossart, David Baratoux, G. S. Orton, Alice Decock, N. Esseiva, Anny Chantal Levasseur-Regourd, J. M. Gómez-Forrellad, C. Rinner, Georg Fischer, F. Meyer, A. Klotz, Jean Lecacheux, M. Ali Dib, T. Boehm, E. Frappa, F. Colas, Alain Maury, Françoise Roques, Philippe Rousselot, Vincent Boudon, J. P. Beaulieu, Alexandre Santerne, Santiago Pérez-Hoyos, Benoit Carry, R. W. Schmude, A. Wesley, B. Tregon, Thomas Widemann, Leigh N. Fletcher, Brigitte Zanda, Agustín Sánchez-Lavega, W. Beisker, M. Delcroix, Bruno Sicardy, F. Kugel, O. Mousis, D. Herald, S. Foglia, J. M. Petit, Jeremie Vaubaillon, L. Maquet, Mirel Birlan, A. Delsanti, L. Buzzi, Jean-Luc Dauvergne, Jean-Pierre Lebreton, Alexis Bouquet, Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Université de Franche-Comté (UFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Escuela Tecnica Superior de Ingenieria Bilbao, Institut d'Astrophysique de Paris (IAP), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Géosciences Paris Sud (GEOPS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Observatoire de Haute-Provence (OHP), Institut Pythéas (OSU PYTHEAS), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS), International Occultation Timing Association European Section (IOTA ES), International Occultation Timing Association European Section, Centre National d'Études Spatiales [Toulouse] (CNES), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, Euraster, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Universidad del Pais Vasco / Euskal Herriko Unibertsitatea [Espagne] (UPV/EHU), 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), Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS), Department of Earth and Planetary Sciences [Piscataway], Rutgers, The State University of New Jersey [New Brunswick] (RU), Rutgers University System (Rutgers)-Rutgers University System (Rutgers), Dynamique terrestre et planétaire (DTP), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Laboratoire Astrophysique de Toulouse-Tarbes (LATT), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Laboratoire Interdisciplinaire Carnot de Bourgogne (LICB), Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS), Institut du Porc, Société Astronomique de France (SAF), Association AstroQueyras, Canberra Astronomical Society, Institut d'Astrophysique et de Géophysique [Liège], Université de Liège, Observatoire Chante-Perdrix, Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), European Southern Observatory (ESO), Departamento de Fı'sica Aplicada I, Association des Utilisateurs de Détecteurs Electroniques (AUDE), Association des Utilisateurs de Détecteurs Electroniques, Association T60, Observatoire Midi-Pyrénées, Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées, Chercheur indépendant, 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 Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), PSL Research University (PSL)-PSL Research University (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut UTINAM (Univers, transport, interfaces, nanostructures, atmosphère et environnement, molécules) (Besançon), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Departamento de Fisica Aplicada [Bilbao], Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA), Institut de recherche en astrophysique et planétologie (IRAP), 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 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)-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, Observatoire Castanet, 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), Association of Universities for Research in Astronomy (AURA), 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 de Astrofísica da Universidade do Porto (CAUP), Universidade do Porto = University of Porto, Joseph Louis LAGRANGE (LAGRANGE), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de recherche pour le développement [IRD] : UR206-Centre National de la Recherche Scientifique (CNRS), Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), Osservatorio Astronomico Schiaparelli, Association Française d'Astronomie - Ciel et Espace (AFA), Association Française d'Astronomie, Département d'astrophysique, Géophysique et Océanographie (AGO), Space Research Institute of Austrian Academy of Sciences (IWF), Austrian Academy of Sciences (OeAW), Department of Atmospheric, Oceanic and Planetary Physics [Oxford] (AOPP), University of Oxford, Astronomical Research Institute [Ashmore], Fundació Privada Observatori Esteve Duran, Astronomical Ring for Access to Spectroscopy (ARAS), International Occultation Timing Association (IOTA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), L'Uranoscope de l'Ile de France, Observatoire de Gretz-Armainvilliers, Department of Physics [Roma Tor Vergata], Università degli Studi di Roma Tor Vergata [Roma], San Pedro de Atacama Celestial Explorations (SPACE), San Pedro de Atacama Celestial Explorations, Observatoire Oukaimeden, JUPOS - Database for Object Positions on Jupiter, British Astronomical Association (BAA), Gordon State College, Laboratoire Ondes et Matière d'Aquitaine (LOMA), Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS), OverSky, Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules ( UTINAM ), Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Franche-Comté ( UFC ), Universidad del Pais Vasco / Euskal Herriko Unibertsitatea ( UPV/EHU ), Institut d'Astrophysique de Paris ( IAP ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), 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 ), Géosciences Paris Sud ( GEOPS ), Université Paris-Sud - Paris 11 ( UP11 ) -Centre National de la Recherche Scientifique ( CNRS ), European Space Astronomy Center ( ESAC ), European Space Agency ( ESA ), 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 ), Société Astronomique de France ( SAF ), International Occultation Timing Association European Section ( IOTA ES ), Observatoire Midi-Pyrénées ( OMP ), 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 ), 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 ), Association of Universities for Research in Astronomy ( AURA ), IMPEC - 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 ), Centro de Astrofísica da Universidade do Porto ( CAUP ), Universidade do Porto [Porto], Joseph Louis LAGRANGE ( LAGRANGE ), Université Nice Sophia Antipolis ( UNS ), Université Côte d'Azur ( UCA ) -Université Côte d'Azur ( UCA ) -Observatoire de la Côte d'Azur, Université Côte d'Azur ( UCA ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire de Minéralogie et Cosmochimie du Museum (LMCM), UMR 7202 ( LMCM ), Muséum National d'Histoire Naturelle ( MNHN ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire Interdisciplinaire Carnot de Bourgogne ( LICB ), Université de Bourgogne ( UB ) -Centre National de la Recherche Scientifique ( CNRS ), Observatoire Midi-Pyrénées and Association T60, Association Française d'Astronomie - Ciel et Espace ( AFA ), Département d'astrophysique, Géophysique et Océanographie ( AGO ), Space Research Institute of Austrian Academy of Sciences ( IWF ), Austrian Academy of Sciences ( OeAW ), Department of Atmospheric, Oceanic and Planetary Physics [Oxford] ( AOPP ), University of Oxford [Oxford], Astronomical Research Institute {Ashmore], Astronomical Ring for Access to Spectroscopy ( ARAS ), Astronomical Ring for Access to Spectroscopy, International Occultation Timing Association ( IOTA ), International Occultation Timing Association, Laboratoire de Physique et Chimie de l'Environnement et de l'Espace ( LPC2E ), Institut national des sciences de l'Univers ( INSU - CNRS ) -Université d'Orléans ( UO ) -Centre National de la Recherche Scientifique ( CNRS ), Department of Physics [Roma], San Pedro de Atacama Celestial Explorations ( SPACE ), British Astronomical Association ( BAA ), University System of Georgia ( USG ), Laboratoire Ondes et Matière d'Aquitaine ( LOMA ), Université de Bordeaux ( UB ) -Centre National de la Recherche Scientifique ( CNRS ), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), 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), European Space Agency (ESA), 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), 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)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), 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), Universidade do Porto, 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), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de recherche pour le développement [IRD] : UR206-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Engineering, [PHYS.ASTR.IM]Physics [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], 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, Planetary Astronomy, 01 natural sciences, Imaging, Photometry, Physics::Popular Physics, Planet, 0103 physical sciences, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, Spectroscopy, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Professional-amateur collaborations, business.industry, Astrophysics::Instrumentation and Methods for Astrophysics, [ SDU.ASTR.IM ] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Astronomy and Astrophysics, [ SDU.ASTR.EP ] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Data science, Exoplanet, Physics::History of Physics, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Planetary science, [ PHYS.ASTR.EP ] Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Space and Planetary Science, Asteroid, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, [ PHYS.ASTR.IM ] Physics [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Interplanetary spaceflight, business, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Instrumentation and Methods for Astrophysics, Amateur, Astrophysics - Earth and Planetary Astrophysics
Abstract: Amateur contributions to professional publications have increased exponentially over the last decades in the field of Planetary Astronomy. Here we review the different domains of the field in which collaborations between professional and amateur astronomers are effective and regularly lead to scientific publications. We discuss the instruments, detectors, softwares and methodologies typically used by amateur astronomers to collect the scientific data in the different domains of interest. Amateur contributions to the monitoring of planets and interplanetary matter, characterization of asteroids and comets, as well as the determination of the physical properties of Kuiper Belt Objects and exoplanets are discussed., 123 pages, Accepted for publication in Experimental Astronomy
Published: 2013

36. Mapping zonal winds at Venus’s cloud tops from ground-based Doppler velocimetry

Author: P. Machado, Olivier Witasse, Emmanuel Lellouch, Thomas Widemann, David Luz, 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), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), and Agence Spatiale Européenne = European Space Agency (ESA)
Subjects: 010504 meteorology & atmospheric sciences, Venus, Atmospheric sciences, 01 natural sciences, Latitude, Atmosphere of Venus, Wind profile power law, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Physics::Atmospheric and Oceanic Physics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Long-slit spectroscopy, [PHYS]Physics [physics], biology, Astronomy and Astrophysics, biology.organism_classification, 13. Climate action, Space and Planetary Science, Local time, Physics::Space Physics, Zonal flow, Astrophysics::Earth and Planetary Astrophysics, Longitude, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Geology
Abstract: The most significant aspect of the general circulation of the atmosphere of Venus is its retrograde super-rotation. A complete characterization of this dynamical phenomenon is crucial for understanding its driving mechanisms. Here we report on ground-based Doppler velocimetry measurements of the zonal winds, based on high resolution spectra from the UV–Visual Echelle Spectrograph (UVES) instrument at ESO’s Very Large Telescope. Under the assumption of predominantly zonal flow, this method allows the simultaneous direct measurement of the zonal velocity across a range of latitudes and local times in the day side. The technique, based on long slit spectroscopy combined with the high spatial resolution provided by the VLT, has provided the first ground-based characterization of the latitudinal profile of zonal wind in the atmosphere of Venus, the first zonal wind field map in the visible, as well as new constraints on wind variations with local time. We measured mean zonal wind amplitudes between 106 ± 21 and 127 ± 14 m/s at latitudes between 18°N and 34°S, with the zonal wind being approximately uniform in 2.6°-wide latitude bands (0.3 arcsec at disk center). The zonal wind profile retrieved is consistent with previous spacecraft measurements based on cloud tracking, but with non-negligible variability in local time (longitude) and in latitude. Near 50° the presence of moderate jets is apparent in both hemispheres, with the southern jet being stronger by ∼10 m/s. Small scale wind variations with local time are also present at low and mid-latitudes.
Published: 2012

37. HDO and SO 2 thermal mapping on Venus: evidence for strong SO 2 variability

Author: Matthew J. Richter, John H. Lacy, Henry G. Roe, Bruno Bézard, Th. Encrenaz, T. Fouchet, Thomas Widemann, Thomas K. Greathouse, 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), Southwest Research Institute [San Antonio] (SwRI), Department of Astronomy [Austin], and University of Texas at Austin [Austin]
Subjects: Physics, [PHYS]Physics [physics], 010504 meteorology & atmospheric sciences, biology, Imaging spectrometer, Astronomy and Astrophysics, Venus, Atmosphere of Mars, Astrophysics, biology.organism_classification, 01 natural sciences, Spectral line, 13. Climate action, Space and Planetary Science, 0103 physical sciences, Mixing ratio, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Mixing (physics), Water vapor, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Line (formation)
Abstract: We have been using the TEXES high-resolution imaging spectrometer at the NASA Infrared Telescope Facility to map sulfur dioxide and deuterated water over the disk of Venus. Observations took place on January 10–12, 2012. The diameter of Venus was 13 arcsec, with an illumination factor of 80%. Data were recorded in the 1344–1370 cm −1 range (around 7.35 μm) with a spectral resolving power of 80 000 and a spatial resolution of about 1.5 arcsec. In this spectral range, the emission of Venus comes from above the cloud top (z = 60–80 km). Four HDO lines and tens of SO2 lines have been identified in our spectra. Mixing ratios have been estimated from HDO/CO2 and SO2/CO2 line depth ratios, using weak neighboring transitions of comparable depths. The HDO maps, recorded on Jan. 10 and Jan. 12, are globally uniform with no significant variation between the two dates. A slight enhancement of the HDO mixing ratio toward the limb might be interpreted as a possible increase of the D/H ratio with height above the cloud level. The mean H2O mixing ratio is found to be 1.5 +/−0.75 ppm, assuming a D/H ratio of 0.0312 (i.e. 200 times the terrestrial value) over the cloud deck. The SO2 maps, recorded each night from Jan. 10 to Jan. 12, show strong variations over the disk of Venus, by a factor as high as 5 to 10. In addition, the position of the maximum SO2 mixing ratio strongly varies on a timescale of 24 h. The maximum SO2 mixing ratio ranges between 75 +/−25 ppb and 125 +/−50 ppb between Jan. 10 and Jan. 12. The high variability of sulfur dioxide is probably a consequence of its very short photochemical lifetime.
Published: 2012

38. New Measurements of Venus Winds with Ground-Based Doppler Velocimetry at CFHT

Author: Machado, Pedro, Thomas Widemann, Luz, David, Peralta, Javier, and Berry, David
Subjects: Venus atmosphere
Abstract: operations with observations from the ground using various techniques and spectral domains (Lellouch and Witasse, 2008). We present an analysis of Venus Doppler winds at cloud tops based on observations made at the Canada France Hawaii 3.6-m telescope (CFHT) with the ESPaDOnS visible spectrograph. These observations consisted of high-resolution spectra of Fraunhofer lines in the visible range (0.37-1.05 μm) to measure the winds at cloud tops using the Doppler shift of solar radiation scattered by cloud top particles in the observer's direction (Widemann et al., 2007, 2008). The observations were made during 19-20 February 2011 and were coordinated with Visual Monitoring Camera (VMC) observations by Venus Express. The complete optical spectrum was collected over 40 spectral orders at each point with 2-5 seconds exposures, at a resolution of about 80000. The observations included various points of the dayside hemisphere at a phase angle of 67°, between +10° and -60° latitude, in steps of 10° , and from +70° to -12° longitude relative to sub-Earth meridian in steps of 12°. The Doppler shift measured in scattered solar light on Venus dayside results from two instantaneous motions: (1) a motion between the Sun and Venus upper cloud particles; (2) a motion between the observer and Venus clouds. The measured Doppler shift, which results from these two terms combined, varies with the planetocentric longitude and latitude and is minimum at meridian ΦN = ΦSun - ΦEarth where the two components subtract to each other for a pure zonal regime. Due to the need for maintaining a stable velocity reference during the course of acquisition using high resolution spectroscopy, we measure relative Doppler shifts to ΦN. The main purpose of our work is to provide variable wind measurements with respect to the background atmosphere, complementary to simultaneous measurements made with the VMC camera onboard the Venus Express. We will present first results from this work, comparing with previous results by the CFHT/ESPaDOnS and VLT-UVES spectrographs (Machado et al., 2012), with Galileo fly-by measurements and with VEx nominal mission observations (Peralta et al., 2007, Luz et al., 2011). Acknowledgements: The authors acknowledge support from FCT through projects PTDC/CTE-AST/110702/2009 and PEst-OE/FIS/UI2751/2011. PM and TW also acknowledge support from the Observatoire de Paris. Lellouch, E., and Witasse, O., A coordinated campaign of Venus ground-based observations and Venus Express measurements, Planetary and Space Science 56 (2008) 1317-1319. Luz, D., et al., Venus's polar vortex reveals precessing circulation, Science 332 (2011) 577-580. Machado, P., Luz, D. Widemann, T., Lellouch, E., Witasse, O, Characterizing the atmospheric dynamics of Venus from ground-based Doppler velocimetry, Icarus, submitted. Peralta J., R. Hueso, A. Sánchez-Lavega, A reanalysis of Venus winds at two cloud levels from Galileo SSI images, Icarus 190 (2007) 469-477. Widemann, T., Lellouch, E., Donati, J.-F., 2008, Venus Doppler winds at Cloud Tops Observed with ESPaDOnS at CFHT, Planetary and Space Science, 56, 1320-1334.
Published: 2012

39. Sunlight refraction in the mesosphere of Venus during the transit on June 8th, 2004

Author: Lorenzo Comolli, Thomas Widemann, A. Rondi, S. Rondi, Jay M. Pasachoff, Bruno Sicardy, P. Sütterlin, Paolo Tanga, J. Arnaud, 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, and Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 010504 meteorology & atmospheric sciences, Physics - History and Philosophy of Physics, FOS: Physical sciences, Venus, 01 natural sciences, Latitude, Photometry (optics), Atmosphere, Atmosphere of Venus, Physics - Geophysics, Planet, 0103 physical sciences, History and Philosophy of Physics (physics.hist-ph), Transit (astronomy), 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), biology, Astronomy, Astronomy and Astrophysics, biology.organism_classification, Refraction, Geophysics (physics.geo-ph), 13. Climate action, Space and Planetary Science, Geology, Astrophysics - Earth and Planetary Astrophysics
Abstract: Many observers in the past gave detailed descriptions of the telescopic aspect of Venus during its extremely rare transits across the Solar disk. In particular, at the ingress and egress, the portion of the planet's disk outside the Solar photosphere has been repeatedly perceived as outlined by a thin, bright arc ("aureole"). Those historical visual observations allowed inferring the existence of Venus' atmosphere, the bright arc being correctly ascribed to the refraction of light by the outer layers of a dense atmosphere. On June 8th, 2004, fast photometry based on electronic imaging devices allowed the first quantitative analysis of the phenomenon. Several observers used a variety of acquisition systems to image the event -- ranging from amateur-sized to professional telescopes and cameras -- thus collecting for the first time a large amount of quantitative information on this atmospheric phenomenon. In this paper, after reviewing some elements brought by the historical records, we give a detailed report of the ground based observations of the 2004 transit. Besides confirming the historical descriptions, we perform the first photometric analysis of the aureole using various acquisition systems. The spatially resolved data provide measurements of the aureole flux as a function of the planetocentric latitude along the limb. A new differential refraction model of solar disk through the upper atmosphere allows us to relate the variable photometry to the latitudinal dependency of scale-height with temperature in the South polar region, as well as the latitudinal variation of the cloud-top layer altitude. We compare our measurements to recent analysis of the Venus Express VIRTIS-M, VMC and SPICAV/SOIR thermal field and aerosol distribution. Our results can be used a starting point for new, more optimized experiments during the 2012 transit event., Comment: Icarus, in press
Published: 2012

40. A Pluto-like radius and a high albedo for the dwarf planet Eris from an occultation

Author: W. J. B. Corradi, G. P. Tozzi, D. N. da Silva Neto, S. Pastor, A. Castro, R. Gil Hutton, Petr Kubánek, P. Santos-Sanz, Felipe Braga-Ribas, L. Cuesta, L. Gutiérrez, E. Lellouch, M. T. Eibe, S. Saravia, R. Vieira Martins, H. Hernández-Toledo, Jean Manfroid, C. Jacques, A. Ramos Gomes, I. de la Cueva, A. Milone, Marcelo Emilio, Juan Fabregat, Stefano Mottola, F. Roques, Martin Jelínek, José M. Madiedo, E. García Melendo, D. Weaver, M. Cebrián, Pilar Montañés-Rodríguez, Audrey Thirouin, A. Ullán, Iain A. Steele, Wilson Reis, Roberto Vázquez, J. Lecacheux, Michaël Gillon, A. J. Castro-Tirado, Marcelo Assafin, Jose Luis Ortiz, Alain Maury, Alfredo Sota, J.A. de los Reyes, C. Harlingten, Bruno Sicardy, Emmanuel Jehin, V. Peris, Alejandro Oscoz, Daniel Hestroffer, G. Muler, R. Sanchez-Ramirez, Nicolás Morales, Alexandre Humberto Andrei, François Colas, Thomas Widemann, F. Organero, Julio Camargo, Fabio P. Santos, S. Pedraz, Rene Duffard, Raoul Behrend, 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 Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Observatório do Valongo/UFRJ [Rio de Janeiro], Universidade Federal do Rio de Janeiro (UFRJ), Institut d'Astrophysique et de Géophysique [Liège], Université de Liège, San Pedro de Atacama Celestial Explorations (SPACE), San Pedro de Atacama Celestial Explorations, Complejo Astronómico El Leoncito [San Juan] (CASLEO), Universidad Nacional de Córdoba [Argentina]-Consejo Nacional de Investigaciones Científicas y Técnicas [Buenos Aires] (CONICET)-Universidad Nacional de San Juan (UNSJ)-Universidad Nacional de la Plata [Argentine] (UNLP), Observatório Nacional/MCT, 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), Observatório do Valongo, Universidade Federal do Rio de Janeiro Ladeira do Pedro Antônio, Universidade Estadual da Zona Oeste (UEZO), Universidade Estadual da Zona Oeste, INAF - Osservatorio Astrofisico di Arcetri (OAA), Istituto Nazionale di Astrofisica (INAF), Caisey Harlingten Observatory, Geneva Observatory, University of Geneva [Switzerland], German Aerospace Center (DLR), Fundació Privada Observatori Esteve Duran, Institut de Ciencies de l'Espai [Barcelona] (ICE-CSIC), Observatorio Astronomico de Valencia, Universitat de València (UV), Facultad de Ciencias Experimentales, Universidad de Huelva, Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Observatorio astronómico de La Hita, Observatorio de la Murta, Centro Astronómico Hispano Alemán, Observatorio de Calar Alto (CAHA), Sociedad Malagueña de Astronomía, Centro Cultural José María Gutiérrez Romero, Astroimagen, Observatorio Nazaret, Liverpool JMU, Instituto de Astrofisica de Canarias (IAC), Observatório Astronomico Christus, Colégio Christus, Observatório CEAMIG-REA, Instituto de Ciências Exatas, Departamento de Física, Universidade Federal de Minas Gerais, Instituto Nacional de Pesquisas Espaciais (INPE), Ministério da Ciência, Tecnologia e Inovação, Universidade Estadual de Ponta Grossa, Universidade Estadual de Ponta Grossa - State University of Ponta Grossa (UEPG), Instituto de Astronomía, Universidad Nacional Autónoma de México (UNAM), Universidad Nacional de Córdoba [Argentina]-Consejo Nacional de Investigaciones Científicas y Técnicas [Buenos Aires] (CONICET)-Universidad Nacional de San Juan [Argentine] (UNSJ)-Universidad Nacional de la Plata [Argentine] (UNLP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Université de Genève = University of Geneva (UNIGE), and Universidad Nacional Autónoma de México = National Autonomous University of Mexico (UNAM)
Subjects: 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Ciencias Físicas, Astronomical unit, Dwarf planet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Orbital eccentricity, Astrophysics, no utilizado, 01 natural sciences, 7. Clean energy, Occultation, dwarf planet, Atmosphere, 0103 physical sciences, Trans-Neptunian object, 010303 astronomy & astrophysics, Eris, 0105 earth and related environmental sciences, Physics, Multidisciplinary, biology, Pluto, Astronomy, biology.organism_classification, Astronomía, 13. Climate action, CIENCIAS NATURALES Y EXACTAS, albedo
Abstract: The dwarf planet Eris is a trans-Neptunian object with an orbital eccentricity of 0.44, an inclination of 44 degrees and a surface composition very similar to that of Pluto. It resides at present at 95.7 astronomical units (1ĝ€‰au is the Earth-Sun distance) from Earth, near its aphelion and more than three times farther than Pluto. Owing to this great distance, measuring its size or detecting a putative atmosphere is difficult. Here we report the observation of a multi-chord stellar occultation by Eris on 6 November 2010 ut. The event is consistent with a spherical shape for Eris, with radius 1,163±6 kilometres, density 2.52±0.05 grams per cm 3 and a high visible geometric albedo,. No nitrogen, argon or methane atmospheres are detected with surface pressure larger than about 10,000 times more tenuous than Pluto's present atmosphere. As Pluto's radius is estimated to be between 1,150 and 1,200 kilometres, Eris appears as a Pluto twin, with a bright surface possibly caused by a collapsed atmosphere, owing to its cold environment. We anticipate that this atmosphere may periodically sublimate as Eris approaches its perihelion, at 37.8 astronomical units from the Sun. © 2011 Macmillan Publishers Limited. All rights reserved. Fil: Sicardy, B.. Universite Pierre et Marie Curie; Francia. Institut Universitaire de France; Francia Fil: Ortiz, J.L.. Consejo Superior de Investigaciones Científicas; España Fil: Assafin, M.. Universidade Federal do Rio de Janeiro; Brasil Fil: Jehin, E.. Université de Liège; Bélgica Fil: Maury, A.. San Pedro de Atacama Celestial Explorations; Chile Fil: Lellouch, E.. Universite Pierre et Marie Curie; Francia Fil: Gil Hutton, Ricardo Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Complejo Astronómico ; Argentina Fil: Braga Ribas, F.. Universite Pierre et Marie Curie; Francia. Ministério de Ciencia, Tecnologia e Innovacao. Observatorio Nacional; Brasil Fil: Colas, F.. Universite Pierre et Marie Curie; Francia Fil: Hestroffer, D.. Universite Pierre et Marie Curie; Francia Fil: Lecacheux, J.. Universite Pierre et Marie Curie; Francia Fil: Roques, F.. Universite Pierre et Marie Curie; Francia Fil: Santos-Sanz, P.. Universite Pierre et Marie Curie; Francia Fil: Widemann, T.. Universite Pierre et Marie Curie; Francia Fil: Morales, N.. Consejo Superior de Investigaciones Científicas; España Fil: Duffard, R.. Consejo Superior de Investigaciones Científicas; España Fil: Thirouin, A.. Consejo Superior de Investigaciones Científicas; España Fil: Castro-Tirado, A.J.. Consejo Superior de Investigaciones Científicas; España Fil: Jelínek, M.. Consejo Superior de Investigaciones Científicas; España Fil: Kubánek, P.. Consejo Superior de Investigaciones Científicas; España Fil: Sota, A.. Consejo Superior de Investigaciones Científicas; España Fil: Sánchez-Ramírez, R.. Consejo Superior de Investigaciones Científicas; España Fil: Andrei, A.H.. Ministério de Ciencia, Tecnologia e Innovacao. Observatorio Nacional; Brasil. Universidade Federal do Rio de Janeiro; Brasil Fil: Camargo, J.I.B.. Ministério de Ciencia, Tecnologia e Innovacao. Observatorio Nacional; Brasil. Universidade Federal do Rio de Janeiro; Brasil Fil: Da Silva Neto, D.N.. Centro Universitário Estadual Da Zona Oeste; . Ministério de Ciencia, Tecnologia e Innovacao. Observatorio Nacional; Brasil Fil: Gomes Jr., A. Ramos. Universidade Federal do Rio de Janeiro; Brasil Fil: Martins, R. Vieira. Universite Pierre et Marie Curie; Francia. Universidade Federal do Rio de Janeiro; Brasil. Ministério de Ciencia, Tecnologia e Innovacao. Observatorio Nacional; Brasil Fil: Gillon, M.. Université de Liège; Bélgica Fil: Manfroid, J.. Université de Liège; Bélgica Fil: Tozzi, G.P.. Osservatorio Astrofisico di Arcetri; Italia Fil: Harlingten, C.. Caisey Harlingten Observatory; Reino Unido Fil: Saravia, S.. San Pedro de Atacama Celestial Explorations; Chile Fil: Behrend, R.. Universidad de Ginebra; Suiza Fil: Mottola, S.. German Aerospace Center; Alemania Fil: Melendo, E. García. Universitat Autònoma de Barcelona; España. Consejo Superior de Investigaciones Científicas; España Fil: Peris, V.. Universidad de Valencia; España Fil: Fabregat, J.. Universidad de Valencia; España Fil: Madiedo, J.M.. Universidad de Huelva; España Fil: Cuesta, L.. Consejo Superior de Investigaciones Científicas; España Fil: Eibe, M.T.. Consejo Superior de Investigaciones Científicas; España Fil: Ullán, A.. Consejo Superior de Investigaciones Científicas; España Fil: Organero, F.. Observatorio astronómico de La Hita; España Fil: Pastor, S.. Observatorio de la Murta; España Fil: De Los Reyes, J.A.. Observatorio de la Murta; España Fil: Pedraz, S.. Centro Astronómico Hispano Alemán; España Fil: Castro, A.. Centro Cultural José María Gutiérrez Romero; España Fil: De La Cueva, I.. Astroimagen; España Fil: Muler, G.. Observatorio Nazaret; España Fil: Steele, I.A.. Liverpool JMU; Reino Unido Fil: Cebrián, M.. Instituto Astrofisico de Canarias; Fil: Montañés-Rodríguez, P.. Instituto Astrofisico de Canarias; España Fil: Oscoz, A.. Instituto Astrofisico de Canarias; España Fil: Weaver, D.. Observatório Astronomico Christus; Brasil Fil: Jacques, C.. Observatório CEAMIG-REA; Brasil Fil: Corradi, W.J.B.. Universidade Federal do Minas Gerais; Brasil Fil: Santos, F.P.. Universidade Federal do Minas Gerais; Brasil Fil: Reis, W.. Universidade Federal do Minas Gerais; Brasil Fil: Milone, A.. Instituto Nacional de Pesquisas Espaciais; Brasil Fil: Emilio, M.. Universidade Estadual de Ponta Grossa; Brasil Fil: Gutiérrez, L.. Universidad Nacional Autónoma de México; México Fil: Vázquez, R.. Universidad Nacional Autónoma de México; México Fil: Hernández Toledo, H.. Universidad Nacional Autónoma de México; México
Published: 2011

41. Transmission spectrum of Venus as a transiting exoplanet

Author: Paolo Tanga, Thomas Widemann, A. Lecavelier des Etangs, Guillaume Gronoff, Jean Lilensten, David Ehrenreich, Alfred Vidal-Madjar, Mathieu Barthelemy, Luc Arnold, 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, and Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Earth and Planetary Astrophysics (astro-ph.EP), biology, 010308 nuclear & particles physics, FOS: Physical sciences, Astronomy and Astrophysics, Venus, Astrophysics, Planetary system, biology.organism_classification, 01 natural sciences, Exoplanet, Astrobiology, Atmosphere, Atmosphere of Venus, 13. Climate action, Space and Planetary Science, Planet, 0103 physical sciences, Transit (astronomy), 010303 astronomy & astrophysics, Circumstellar habitable zone, ComputingMilieux_MISCELLANEOUS, Astrophysics - Earth and Planetary Astrophysics
Abstract: On 5-6 June 2012, Venus will be transiting the Sun for the last time before 2117. This event is an unique opportunity to assess the feasibility of the atmospheric characterisation of Earth-size exoplanets near the habitable zone with the transmission spectroscopy technique and provide an invaluable proxy for the atmosphere of such a planet. In this letter, we provide a theoretical transmission spectrum of the atmosphere of Venus that could be tested with spectroscopic observations during the 2012 transit. This is done using radiative transfer across Venus' atmosphere, with inputs from in-situ missions such as Venus Express and theoretical models. The transmission spectrum covers a range of 0.1-5 {\mu}m and probes the limb between 70 and 150 km in altitude. It is dominated in UV by carbon dioxide absorption producing a broad transit signal of ~20 ppm as seen from Earth, and from 0.2 to 2.7 {\mu}m by Mie extinction (~5 ppm at 0.8 {\mu}m) caused by droplets of sulfuric acid composing an upper haze layer above the main deck of clouds. These features are not expected for a terrestrial exoplanet and could help discriminating an Earth-like habitable world from a cytherean planet., Comment: 4 pages, 3 figures, 1 table. Figure 3 and Table 1 will be only available on-line. Table 1 will be fully available at the CDS. Accepted for publication in Astronomy and Astrophysics (Letter)
Published: 2011
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42. Venus wind map at cloud top level with the MTR/THEMIS visible spectrometer. I. Instrumental performance and first results

Author: François-Xavier Schmider, Patrick Gaulme, B. Gelly, Catherine Grec, Thomas Widemann, Arturo López Ariste, 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), Pôle Planétologie du LESIA, 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)-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), Laboratoire Hippolyte Fizeau (FIZEAU), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), and Télescope Héliographique pour l'Étude du Magnétisme et des Instabilités Solaires (THEMIS)
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), Spectrometer, biology, Cloud top, Equator, Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, Astronomy and Astrophysics, Venus, biology.organism_classification, Solar telescope, Atmosphere, Altitude, Space and Planetary Science, Observatory, Physics::Space Physics, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Geology, Physics::Atmospheric and Oceanic Physics, Remote sensing, Astrophysics - Earth and Planetary Astrophysics
Abstract: Solar light gets scattered at cloud top level in Venus' atmosphere, in the visible range, which corresponds to the altitude of 67 km. We present Doppler velocity measurements performed with the high resolution spectrometer MTR of the Solar telescope THEMIS (Teide Observatory, Canary Island) on the sodium D2 solar line (5890 \AA). Observations lasted only 49 min because of cloudy weather. However, we could assess the instrumental velocity sensitivity, 31 m/s per pixel of 1 arcsec, and give a value of the amplitude of zonal wind at equator at 151 +/- 16 m/s., Comment: 17 pages, 12 figures
Published: 2010

43. The science of EChO

Author: James Frith, Marina Galand, Emmanuel Lellouch, Antonino La Barbera, M. J. Barlow, Marcell Tessenyi, Peter Doel, Ignasi Ribas, Jesus Maldonado Prado, Sergey N. Yurchenko, David M. Kipping, Pactrick Guio, Roy van Boekel, Peter H. Hauschildt, Remco de Kok, Antonio Maggio, Maria R. Zapatero-Osorio, David Pinfield, Emanuele Pace, Mercedes Lopez Morales, Raman K. Prinja, Géza Kovács, Mark G. Swain, Angioletta Coradini, Richard P. Nelson, Patrick Gaulme, Julianne I. Moses, Ingo Mueller-Wodarg, Jean-Philippe Beaulieu, Alan D. Aylward, Gáspár Á. Bakos, Thomas Widemann, Giovanni Strazzulla, Céline Cavarroc, Manuel Guedel, Caitlin A. Griffith, Olivier Hainaut, S. J. Fossey, Pascal Bordé, Ennio Poretti, Giorgio Savini, Jeroen Bouwman, Jean-Pierre Maillard, Eric Pantin, Mercedes López-Morales, Leen Decin, Miguel A. Lopez Valverde, Olivier Mousis, Peter A. R. Ade, Pieter Deroo, Olivier Demangeon, Kevin Heng, James Y-K. Cho, Angela Ciaravella, Amaya Moro-Martin, Daphne Stam, Tristan Guillot, Bruno Bézard, Franck Selsis, Roger V. Yelle, Lisa Kaltenegger, Pascal Fouqué, Alessandro Sozzetti, Alberto Adriani, Linda R. Brown, Giovanna Tinetti, Loredana Prisinzano, Giuseppina Micela, Thomas Henning, Vincent Coudé du Foresto, Craig B. Agnor, Ulrich Grözinger, Yuk Yung, Michael Meyer, Robert J. Hargreaves, Marc Ollivier, Ansgar Reiners, Ricardo Hueso, Enzo Pascale, Alan Smith, Nicholas Achilleos, Dimitar Sasselov, Robin Wordsworth, Jonathan Tennyson, Bruce Swinyard, Carlos Allende Prieto, Sergio Molinari, Manuel López-Puertas, Peter F. Bernath, David Heyrovsky, Ignas Snellen, Bruno Sicardy, Oliver Krause, Gautam Vasisht, Steve Miller, Christophe Lovi, Matthew James Griffin, Athena Coustenis, Napoléon Nguyen Tuong, Ingo Waldmann, Glenn S. Orton, Giuseppe Leto, B. Samuel, Patrick Kervella, Pierre F. L. Maxted, F. J. Martin-Torres, Lee Grenfell, Patrick G. J. Irwin, Stefano Pezzuto, Cristina Afonso, Olivier Grasset, Thérèse Encrenaz, Jonay I. González Hernández, Helmut Lammer, Davide Grassi, Serena Viti, Enric Palle, Tommi Koskinen, Jorge Sanz Forcada, Glenn J. White, Camilla Danielski, François Forget, Leigh N. Fletcher, Jean-Michel Reess, Arnaud Cassan, J. B. Marquette, Matteo Focardi, D. Montes, R. J. Barber, Sandrine Vinatier, Charles S. Cockell, Lars Stixrude, Pierre Drossart, University College of London [London] (UCL), Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Department of Physics and Astronomy [UCL London], Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), 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)-Centre National de la Recherche Scientifique (CNRS)-École des Ponts ParisTech (ENPC)-École polytechnique (X)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Istituto di Fisica dello Spazio Interplanetario (INAF), Consiglio Nazionale delle Ricerche [Roma] (CNR), 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), Département d'Astrophysique (ex SAP) (DAP), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1, Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Institut d'Astrophysique de Paris (IAP), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Liquides Ioniques et Interfaces Chargées (LI2C), Université Pierre et Marie Curie - Paris 6 (UPMC)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Palermo (OAPa), Istituto Nazionale di Astrofisica (INAF), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), SRON Netherlands Institute for Space Research (SRON), University of Calgary, 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), School of Physics and Astronomy [London], Queen Mary University of London (QMUL), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Astronomische Rechen-Institut [Heidelberg] (ARI), Zentrum für Astronomie der Universität Heidelberg (ZAH), Universität Heidelberg [Heidelberg]-Universität Heidelberg [Heidelberg], Planetary and Space Sciences Research Institute [Milton Keynes] (PSSRI), Centre for Earth, Planetary, Space and Astronomical Research [Milton Keynes] (CEPSAR), The Open University [Milton Keynes] (OU)-The Open University [Milton Keynes] (OU), Department of Atmospheric, Oceanic and Planetary Physics [Oxford] (AOPP), University of Oxford [Oxford], Institut Pierre-Simon-Laplace (IPSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National d'Études Spatiales [Toulouse] (CNES)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Laboratoire Astrophysique de Toulouse-Tarbes (LATT), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-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), Blackett Laboratory, Imperial College London, Istituto di Fisica dello Spazio Interplanetario (IFSI), Consiglio Nazionale delle Ricerche (CNR), Escuela Superior de Ingenieria, Universidad del Pais Vasco / Euskal Herriko Unibertsitatea [Espagne] (UPV/EHU), Harvard-Smithsonian Center for Astrophysics (CfA), Smithsonian Institution-Harvard University [Cambridge], Space Research Institute of Austrian Academy of Sciences (IWF), Austrian Academy of Sciences (OeAW), Department of Science and Technology Studies [London] (STS), Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Institut Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), Imperial College Healthcare NHS Trust, STFC Rutherford Appleton Laboratory (RAL), Science and Technology Facilities Council (STFC), Department of Physics and Astronomy [Milton Keynes], The Open University [Milton Keynes] (OU), Université Nice Sophia Antipolis (1965 - 2019) (UNS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1 (UB), 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 Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Universität Heidelberg [Heidelberg] = Heidelberg University-Universität Heidelberg [Heidelberg] = Heidelberg University, University of Oxford, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), 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), Harvard University-Smithsonian Institution, Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Planétologie et Géodynamique UMR6112 (LPG), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Nantes - Faculté des Sciences et des Techniques, Université de Nantes (UN)-Université de Nantes (UN)-Université d'Angers (UA), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Centre National de la Recherche Scientifique (CNRS)-ESPCI ParisTech-Université Pierre et Marie Curie - Paris 6 (UPMC), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), California Institute of Technology (CALTECH)-NASA, École normale supérieure - Paris (ENS Paris)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National d'Études Spatiales [Toulouse] (CNES)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, and Harvard University [Cambridge]-Smithsonian Institution
Subjects: Solar System, [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], Luchtkwaliteit, 01 natural sciences, 7. Clean energy, Astrobiology, Air Quality, Kepler-47, Planet, formation [Planetary systems], 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, planets and satellites: formation, Kepler-62, 010303 astronomy & astrophysics, planetary systems, Astrophysics::Galaxy Astrophysics, QC, Physics, 010308 nuclear & particles physics, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, Astronomy and Astrophysics, planets and satellites: general, Planetary system, Exoplanet, general [Planets and satellites], planetary systems: formation, Planetary systems, 13. Climate action, Space and Planetary Science, Terrestrial planet, Planetary systems: formation, Planets and satellites: formation, Planets and satellites: general, Astrophysics::Earth and Planetary Astrophysics, Circumstellar habitable zone, formation [Planets and satellites]
Abstract: The science of extra-solar planets is one of the most rapidly changing areas of astrophysics and since 1995 the number of planets known has increased by almost two orders of magnitude. A combination of ground-based surveys and dedicated space missions has resulted in 560-plus planets being detected, and over 1200 that await confirmation. NASA's Kepler mission has opened up the possibility of discovering Earth-like planets in the habitable zone around some of the 100,000 stars it is surveying during its 3 to 4-year lifetime. The new ESA's Gaia mission is expected to discover thousands of new planets around stars within 200 parsecs of the Sun. The key challenge now is moving on from discovery, important though that remains, to characterisation: what are these planets actually like, and why are they as they are?In the past ten years, we have learned how to obtain the first spectra of exoplanets using transit transmission and emission spectroscopy. With the high stability of Spitzer, Hubble, and large ground-based telescopes the spectra of bright close-in massive planets can be obtained and species like water vapour, methane, carbon monoxide and dioxide have been detected. With transit science came the first tangible remote sensing of these planetary bodies and so one can start to extrapolate from what has been learnt from Solar System probes to what one might plan to learn about their faraway siblings. As we learn more about the atmospheres, surfaces and near-surfaces of these remote bodies, we will begin to build up a clearer picture of their construction, history and suitability for life.The Exoplanet Characterisation Observatory, EChO, will be the first dedicated mission to investigate the physics and chemistry of Exoplanetary Atmospheres. By characterising spectroscopically more bodies in different environments we will take detailed planetology out of the Solar System and into the Galaxy as a whole.EChO has now been selected by the European Space Agency to be assessed as one of four M3 mission candidates.
Published: 2010

44. Titania's radius and an upper limit on its atmosphere from the September 8, 2001 stellar occultation

Author: Emmanuel Lellouch, F. Díaz, Ph. Dupouy, P. Figuereido, B. Mitchell, C. Birnbaum, W. Sutherland, H. Mendt, C. Labordena, C. Martinez, P. Valdes Sada, F. Schwartz, P. Burlot, E. van Ballegoij, C. Clarasso-Llauger, J.-F. Coliac, C. Sire, R. Jones, M. Kretlow, P. Maley, S. Rivaud, J. Lecacheux, J.M. Winkel, A. Cidadão, C. Saraiva, R. E. Hill, C. Marlot, S. Pau, F. Colas, F. Roques, E. López, C. Marciano, M. Gabaldá-Sánchez, C. Demeautis, P. Coelho, A. Roca, C. Schnabel, Jean-Eudes Arlot, Pedro Ré, R. Gonçalves, R. Hernández, C. Buil, A.J. Elliott, E. Masana, A. Ardanuy, C. Guillén, J.-F. Lecampion, F. Casarramona, William B. Hubbard, X. Simbaña, L. Rivas, L. Omar Porras, H. Callender, E. Brochard, J. L. Ortiz, M. Rapaport, D. Pulupa, A. Peña, J. Gonçalves, G. Sánchez, G. Rau, A. Hernández, B.M. Ewen-Smith, A. Arnal, Pascal Dubreuil, C. Lambin, C. R. Hills, E. Pallo, K. Daiffallah, X. Otazu-Porter, Richard Miles, Ch. Marlot, R. Cósias, S. Radaelli, B. Bayle, V. Ladino, C. Leyrat, P. Rodas, A. Klotz, R. Dusser, J. Clérigo, B. Wilson, E. Bredner, D. Cornwall, D. Ford, O. Labrevoir, D. Fernández, W. Barrow, Erika Castro, Bruno Sicardy, M. Mascaró, O. Chaptal, E. Simian, E. Recalde, B. Stephanus, Ricard Casas, F. Tonel, William Thuillot, V. Desnoux, J. Berthier, C. Oliveira, J. Laurindo Sobrinho, M. Rieugnié, P. Henriquet, J. Piraux, P. Rosenzweig, Steven N. Ward, G. Eleizalde, A. Yajamín, C. Sauzeaud, J. Aloy Doménech, K. Vieira, M. Lavayssière, P. Langlais, T. Rafaelli, G. Bouderand, J. Santiago, R. Delmas, M. Imbert, H. Denzau, J. A. Ros, A. Valencia, T. Lizardo, F. Teodoro de Gois, J. Porto, J. Fulgence, J.-P. Cazard, O. Contreras, F. Moreno, W. Beisker, J. Lockhart, T. Platt, F. Gorry, J. Afonso da Silva Mendes, R. Percz, R. Nunes, E. Guzmán, V. Ferrer, D. Dunham, S. Bumgarner, J. Fernández-Arozena, A.M. Blommers, C. Jasinski, O. Canales-Moreno, C. Reis, L.L. Martín-Rodríguez, M. Joaquim, O. Naranjo, D. Marchais, Thomas Widemann, C. Cremaschini, P.O. Pujat, and C. Cavadore
Subjects: Physics, 010504 meteorology & atmospheric sciences, Uranus, Astronomy, Astronomy and Astrophysics, Solar radius, Radius, Ephemeris, 01 natural sciences, Occultation, Atmosphere, 13. Climate action, Space and Planetary Science, Angular diameter, 0103 physical sciences, Physical Sciences, Polar, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: On September 8, 2001 around 2 h UT, the largest uranian moon, Titania, occulted Hipparcos star 106829 (alias SAO 164538, a V = 7.2 , K0 III star). This was the first-ever observed occultation by this satellite, a rare event as Titania subtends only 0.11 arcsec on the sky. The star's unusual brightness allowed many observers, both amateurs or professionals, to monitor this unique event, providing fifty-seven occultations chords over three continents, all reported here. Selecting the best 27 occultation chords, and assuming a circular limb, we derive Titania's radius: R T = 788.4 ± 0.6 km ( 1 - σ error bar). This implies a density of ρ = 1.711 ± 0.005 g cm −3 using the value G M = ( 2.343 ± 0.006 ) × 10 11 m 3 s −2 derived by Taylor [Taylor, D.B., 1998. Astron. Astrophys. 330, 362–374]. We do not detect any significant difference between equatorial and polar radii, in the limit r eq − r po = − 1.3 ± 2.1 km , in agreement with Voyager limb image retrieval during the 1986 flyby. Titania's offset with respect to the DE405 + URA027 (based on GUST86 theory) ephemeris is derived: Δ α T cos ( δ T ) = − 108 ± 13 mas and Δ δ T = − 62 ± 7 mas (ICRF J2000.0 system). Most of this offset is attributable to a Uranus' barycentric offset with respect to DE405, that we estimate to be: Δ α U cos ( δ U ) = − 100 ± 25 mas and Δ δ U = − 85 ± 25 mas at the moment of occultation. This offset is confirmed by another Titania stellar occultation observed on August 1st, 2003, which provides an offset of Δ α T cos ( δ T ) = − 127 ± 20 mas and Δ δ T = − 97 ± 13 mas for the satellite. The combined ingress and egress data do not show any significant hint for atmospheric refraction, allowing us to set surface pressure limits at the level of 10–20 nbar. More specifically, we find an upper limit of 13 nbar ( 1 - σ level) at 70 K and 17 nbar at 80 K, for a putative isothermal CO2 atmosphere. We also provide an upper limit of 8 nbar for a possible CH4 atmosphere, and 22 nbar for pure N2, again at the 1 - σ level. We finally constrain the stellar size using the time-resolved star disappearance and reappearance at ingress and egress. We find an angular diameter of 0.54 ± 0.03 mas (corresponding to 7.5 ± 0.4 km projected at Titania). With a distance of 170 ± 25 parsecs, this corresponds to a radius of 9.8 ± 0.2 solar radii for HIP 106829, typical of a K0 III giant.
Published: 2009

45. Monitoring of ozone trend by stellar occultations: the GOMOS instrument

Author: S. Korpela, Erkki Kyrölä, R. J. Pellinen, Gérard Mégie, Jean-Loup Bertaux, Eric Chassefière, P. Simon, and Thomas Widemann
Subjects: Atmospheric Science, Ozone, Aerospace Engineering, Astronomy and Astrophysics, Global Ozone Monitoring by Occultation of Stars, Atmospheric sciences, Astronomical spectroscopy, Latitude, law.invention, Atmosphere, Telescope, chemistry.chemical_compound, Geophysics, Altitude, chemistry, Space and Planetary Science, law, General Earth and Planetary Sciences, Environmental science, Absorption (electromagnetic radiation)
Abstract: As a part of the payload of the first European Polar Platform, the GOMOS instrument has been proposed by a group of 25 scientists from six countries. It consists of a telescope feeding two spectrographs, mounted on a dedicated steerable platform. The transmittance of the atmosphere between 250 and 675 nm is measured by comparing the spectrum of a star outside the atmosphere, and through it. The ozone tangential column is determined from its UV and Chappuis band absorption. This self-calibrated method is particularly well suited for the study of ozone long term trend. The altitude of each single measurement is precisely known (± 50 m), independently of altitude uncertainties. About 25 stellar occultations per orbit, and 350 per day, spread over all latitudes can be performed from 90 km down to 15–20 km of altitude. NO 2 , NO 3 , H 2 O, T(z) and aerosols are also simultaneously determined, important parameters associated to the ozone equilibrium. The ability to measure ozone long-term trends is calculated.
Published: 1991

46. Venus Doppler winds at cloud tops observed with ESPaDOnS at CFHT

Author: Thomas Widemann, Jean-François Donati, Emmanuel Lellouch, 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), Laboratoire Astrophysique de Toulouse-Tarbes (LATT), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-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), 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), and 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)
Subjects: 010504 meteorology & atmospheric sciences, Venus, 01 natural sciences, Spectral line, law.invention, Mesosphere, Telescope, symbols.namesake, Phase angle (astronomy), law, 0103 physical sciences, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, Spacecraft, biology, business.industry, [SDU.ASTR.HE]Sciences of the Universe [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], Astronomy, Astronomy and Astrophysics, biology.organism_classification, Fraunhofer lines, 13. Climate action, Space and Planetary Science, symbols, business, Doppler effect
Abstract: International audience; We present new wind measurements in Venus' lower mesosphere from visible spectroscopy during the 2007 worldwide coordinated ground campaign in support of ESA's Venus Express mission. These observations consisted of high-resolution spectra of Fraunhofer lines in the entire visible range (0.37 1.05 μm) to measure the winds near 68 km using the Doppler shift of solar radiation scattered by clouds toward the observer's direction. The observations included various points of the dayside hemisphere at a phase angle of ˜109°. We took advantage of two symmetrical elongations in July and September 2007 at Canada France Hawaii's 3.6-m telescope. Kinematical fits to the Doppler winds provide a mean equatorial velocity of (104±10) m s‑1 for the zonal retrograde flow. This velocity agrees quite well with the mean value obtained by tracking the UV markings from several spacecraft.
Published: 2008

47. New wind measurements in Venus' lower mesosphere from visible spectroscopy

Author: Alain Campargue, Thomas Widemann, Emmanuel Lellouch, 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), Pôle Planétologie du LESIA, 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)-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), Laboratoire de Spectrométrie Physique (LSP), and Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, biology, Doppler spectroscopy, Flow (psychology), Astronomy and Astrophysics, Venus, Astrophysics, Geophysics, biology.organism_classification, Mesosphere, Fraunhofer lines, Superposition principle, symbols.namesake, Altitude, Space and Planetary Science, Wind shear, symbols, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; The dynamics of Venus' mesosphere (70-110 km) is characterized by the superposition of two different wind regimes: (1) Venus' retrograde superrotation; (2) a sub-solar to anti-solar (SS-AS) flow pattern, driven by solar EUV heating on the sunlit hemisphere. Here, we report on new ground-based velocity measurements in the lower part of the mesosphere. We took advantage of two essentially symmetric Venus elongations in 2001 and 2002 to perform high-resolution Doppler spectroscopy ( R=120,000) in 12C 16O 2 visible lines of the 5 nu3 band and in a few solar Fraunhofer lines near 8700 Å. These measurements, mapped over several points on Venus' illuminated hemisphere, probe the region of cloud tops. More precisely, the solar Fraunhofer lines sample levels a few kilometers below the UV features (i.e. near ˜67 km), while the CO 2 lines probe an altitude higher by about 7 km. The wind field over Venus' disk is retrieved with an rms uncertainty of 15-25 m s -1 on individual measurements. Kinematical fit to a one- or two-component circulation model indicates the dominance of the zonal retrograde flow with a mean equatorial velocity of ˜75 m s -1, exhibiting very strong day-to-day variations (±65 m s -1). Results are very consistent for the two kinds of lines, suggesting a negligible vertical wind shear over 67-74 km. The SS-AS flow is not detected in single-day observations, but combining the results from all data suggests that this component may invade the lower mesosphere with a ˜40 m s -1 velocity.
Published: 2007

48. The two Titan stellar occultations of 14 November 2003

Author: M. Kidger, H. Lüdemann, B. Thomé, F. Bode, Daisuke Baba, C. Martinez, François Colas, C. Tegtmeier, D. Fiel, Jean Lecacheux, Takahiro Nagayama, M. Kretlow, P. Schoenau, T. Payet, Françoise Roques, S. Renner, Brian Fraser, Ian S. Glass, M. Rapaport, H. J. Bode, D. Neubauer, M. Hernandez, P. Meintjies, J. P. Teng, Robert R. Howell, C. Turk, S. Lacour, W. Beisker, F. Hund, C. Etienne, O. Naranjo, Bruno Sicardy, Tetsuya Nagata, Thomas Widemann, A. Bellucci, Terry J. Jones, Francesca Ferri, K.-L. Bath, E. Frappa, S. Itting-Enke, J. Lüdemann, A. Jansen, Agnes Fienga, Emmanuel Lellouch, A. Tegtmeier, G. Hesler, J. L. Ortiz, S. Pau, P. Rosenzweig, A. Peyrot, M. Vignand, C. DeWitt, 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), Pôle Astronomie du LESIA, 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)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Ingénieurs, Techniciens et Administratifs, Pôle Planétologie du LESIA, 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)-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), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), International Occultation Timing Association, European Section (IOTA/ES), Centro Interdipartimentale di Studi e Attività Spaziali 'Giuseppe Colombo', Università di Padova (CISAS), Observatoire de Paris, Université Paris sciences et lettres (PSL), Instituto Superior de Ciencias Astronómicas, South African Astronomical Observatory (SAAO), Department of Astrophysics, Nagoya University, Windhoek, Hakos Guestfarm, Astronomical Society of Southern Africa, Boyden Observatory, University of the Free State, Association des Utilisateurs de Détecteurs Electroniques (AUDE), Association des Utilisateurs de Détecteurs Electroniques, Lycée Stanislas, Paris, Astronef-Planétarium de Saint-Etienne, Observatoire astronomique des Makes, Association Réunionnaise pour l'Etude du Ciel Austral (ARECA), Wyoming InfraRed Observatory, Department of Physics and Astronomy, Instituto de Astrofísica de Canarias (IAC), Instituto de Astrofisica de Andalucia, CSIC (IAA), Universidad de Los Andes, Facultad de Ciencias, Departamento de Física, Grupo de Astrofísica Teórica, Observatoire aquitain des sciences de l'univers (OASU), and Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Atmospheric Science, Haze, Equator, Soil Science, Aquatic Science, Oceanography, Atmospheric sciences, Latitude, symbols.namesake, Altitude, Geochemistry and Petrology, Earth and Planetary Sciences (miscellaneous), Southern Hemisphere, Stratosphere, Earth-Surface Processes, Water Science and Technology, Ecology, Paleontology, Forestry, Light curve, Geophysics, Space and Planetary Science, [SDU]Sciences of the Universe [physics], symbols, Titan (rocket family), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Geology
Abstract: [1] We report the observation of two stellar occultations by Titan on 14 November 2003, using stations in the Indian Ocean, southern Africa, Spain, and northern and southern Americas. These occultations probed altitudes between ∼550 and 250 km (∼1 to 250 μbar) in Titan's upper stratosphere. The light curves reveal a sharp inversion layer near 515 ± 6 km altitude (1.5 μbar pressure level), where the temperature increases by 15 K in only 6 km. This layer is close to an inversion layer observed fourteen months later by the Huygens HASI instrument during the entry of the probe in Titan's atmosphere on 14 January 2005 [Fulchignoni et al., 2005]. Central flashes observed during the first occultation provide constraints on the zonal wind regime at 250 km, with a strong northern jet (∼200 m s -1 ) around the latitude 55°N, wind velocities of ∼150 m s -1 near the equator, and progressively weaker winds as more southern latitudes are probed. The haze distribution around Titan's limb at 250 km altitude is close to that predicted by the Global Circulation Model of Rannou et al. (2004) in the southern hemisphere, but a clearing north of 40°N is necessary to explain our data. This contrasts with Rannou et al.'s (2004) model, which predicts a very thick polar hood over Titan's northern polar regions. Simultaneous observations of the flashes at various wavelengths provide a dependence of τ ∝ λ -q , with q = 1.8 ± 0.5 between 0.51 and 2.2 μm for the tangential optical depth of the hazes at 250 km altitude.
Published: 2006

49. Charon's size and an upper limit on its atmosphere from a stellar occultation

Author: Jean Lecacheux, J-F Lecampion, O. Mousis, Daniela Lazzaro, S. Renner, D. N. da Silva Neto, E. Hummel, C. Jacques, E. Pimentel, Carlos Feinstein, Gonzalo Tancredi, B Gaillard, R. Vieira Martins, Alvaro Alvarez-Candal, M. Lavayssière, Marcelo Assafin, S. Lacour, H. Levato, F. Mallia, E. Frappa, O. Marco, Emmanuel Lellouch, C. H. Veiga, Olivier Hainaut, François Colas, Françoise Roques, T Momiyama, F Doncel, Frédéric Vachier, S. Pau, F Carrier, Eric Gendron, M. di Sora, Philippe Rousselot, Bruno Sicardy, W. Beisker, Alexandre Humberto Andrei, D. Weaver, Gianluca Masi, N. Ageorges, Raoul Behrend, Francois Lacombe, Thomas Widemann, A. Bellucci, Alain Maury, 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), Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire aquitain des sciences de l'univers (OASU), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Multidisciplinary, Pluto, 010504 meteorology & atmospheric sciences, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Satellites, Ciencias Físicas, Moons of Pluto, Astronomy, Radius, Mass ratio, Charon, 01 natural sciences, 7. Clean energy, Occultation, Astronomía, Atmosphere, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Planet, 0103 physical sciences, 010303 astronomy & astrophysics, CIENCIAS NATURALES Y EXACTAS, 0105 earth and related environmental sciences, Double planet
Abstract: Pluto and its satellite, Charon (discovered in 1978; ref. 1), appear to form a double planet, rather than a hierarchical planet/satellite couple. Charon is about half Pluto's size and about one-eighth its mass. The precise radii of Pluto and Charon have remained uncertain, leading to large uncertainties on their densities2. Although stellar occultations by Charon are in principle a powerful way of measuring its size, they are rare, as the satellite subtends less than 0.3 microradians (0.06 arcsec) on the sky. One occultation (in 1980) yielded a lower limit of 600 km for the satellite's radius 3, which was later refined to 601.5 km (ref. 4). Here we report observations from a multi-station stellar occultation by Charon, which we use to derive a radius, RC = 603.6 ± 1.4 km (1σ), and a density of ρ = 1.71 ± 0.08 g cm-3. This occultation also provides upper limits of 110 and 15 (3σ) nanobar for an atmosphere around Charon, assuming respectively a pure nitrogen or pure methane atmosphere. © 2006 Nature Publishing Group. Fil: Sicardy, B.. Universite Pierre et Marie Curie; Francia. Gepi - Galaxies, Etoiles, Physique, Instrumentation; Fil: Bellucci, A.. Gepi - Galaxies, Etoiles, Physique, Instrumentation; Fil: Gendron, E.. Gepi - Galaxies, Etoiles, Physique, Instrumentation; Fil: Lacombe, F.. Gepi - Galaxies, Etoiles, Physique, Instrumentation; Fil: Lacour, S.. Gepi - Galaxies, Etoiles, Physique, Instrumentation; Fil: Lecacheux, J.. Gepi - Galaxies, Etoiles, Physique, Instrumentation; Fil: Lellouch, E.. Gepi - Galaxies, Etoiles, Physique, Instrumentation; Fil: Renner, S.. Gepi - Galaxies, Etoiles, Physique, Instrumentation; Fil: Pau, S.. Gepi - Galaxies, Etoiles, Physique, Instrumentation; Fil: Roques, F.. Gepi - Galaxies, Etoiles, Physique, Instrumentation; Fil: Widemann, T.. Gepi - Galaxies, Etoiles, Physique, Instrumentation; Fil: Colas, F.. Imcce - Institut de Mecanique Celeste Et de Calcul Des Ephemerides; Fil: Vachier, F.. Imcce - Institut de Mecanique Celeste Et de Calcul Des Ephemerides; Fil: Martins, R. Vieira. Imcce - Institut de Mecanique Celeste Et de Calcul Des Ephemerides; . Ministério de Ciencia, Tecnologia e Innovacao. Observatorio Nacional; Brasil Fil: Ageorges, N.. European Southern Observatory Santiago; Chile Fil: Hainaut, O.. European Southern Observatory Santiago; Chile Fil: Marco, O.. European Southern Observatory Santiago; Chile Fil: Beisker, W.. International Occultation Timing Association; Fil: Hummel, E.. International Occultation Timing Association; Fil: Feinstein Baigorri, Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Instituto de Ciencias Astronómicas, de la Tierra y del Espacio. Universidad Nacional de San Juan. Instituto de Ciencias Astronómicas, de la Tierra y del Espacio; Argentina Fil: Levato, Orlando Hugo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Complejo Astronómico ; Argentina Fil: Maury, A.. Gene Shoemaker Observatory; Chile Fil: Frappa, E.. Planétarium de Saint-etienne; Fil: Gaillard, B.. Association Des Utilisateurs de Détecteurs Electroniques (aude); Fil: Lavayssière, M.. Association Des Utilisateurs de Détecteurs Electroniques (aude); Fil: Di Sora, M.. Campo Catino Austral Observatory; Chile Fil: Mallia, F.. Campo Catino Austral Observatory; Chile Fil: Masi, G.. Campo Catino Austral Observatory; Chile. Universita Tor Vergata; Italia Fil: Behrend, R.. Universidad de Ginebra; Suiza Fil: Carrier, F.. Universidad de Ginebra; Suiza Fil: Mousis, O.. Observatoire de Besancon; Fil: Rousselot, P.. Observatoire de Besancon; Fil: Alvarez Candal, Alvaro Augusto. Ministério de Ciencia, Tecnologia e Innovacao. Observatorio Nacional; Brasil Fil: Lazzaro, D.. Ministério de Ciencia, Tecnologia e Innovacao. Observatorio Nacional; Brasil Fil: Veiga, C.. Ministério de Ciencia, Tecnologia e Innovacao. Observatorio Nacional; Brasil Fil: Andrei, A.H.. Ministério de Ciencia, Tecnologia e Innovacao. Observatorio Nacional; Brasil. Universidade Federal do Rio de Janeiro; Brasil Fil: Assafin, M.. Universidade Federal do Rio de Janeiro; Brasil Fil: Da Silva Neto, D.N.. Universidade Federal do Rio de Janeiro; Brasil Fil: Jacques, C.. Observatório CEAMIG-REA; Brasil Fil: Pimentel, E.. Observatório CEAMIG-REA; Brasil Fil: Weaver, D.. Universidade de Fortaleza; Fil: Lecampion, J.-F.. Observatoire Aquitain Des Sciences de L'univers; Fil: Doncel, F.. Universidad Nacional de Asunción; Paraguay Fil: Momiyama, T.. Universidad Nacional de Asunción; Paraguay Fil: Tancredi, G.. Facultad de Ciencias; Uruguay
Published: 2006

50. Large changes in Pluto's atmosphere as revealed by recent stellar occultations

Author: Bruno Sicardy, C. Montalvo, S. Renner, E. Raynaud, Jason Spyromilio, Francois Lacombe, Jean Lecacheux, E. Recalde, Alain Maury, Agnes Fienga, Thomas Widemann, Jean-Charles Cuillandre, H. Levato, L. Porras, C. Leyrat, Christopher Lidman, Emmanuel Lellouch, Eric Gendron, M. Schultheis, S. Carrillo, O. Naranjo, W. Beisker, Roberto Gilmozzi, Audrey Delsanti, P. Rosenzweig, Rene Duffard, Françoise Roques, François Colas, Anne-Marie Lagrange, Olivier Hainaut, H. Calderón, F. Díaz, D. Barría, L. Gaviria Cavero, M. Kretlow, A. Carvajal, K. Brooks, R. Campos, C. Birnbaum, Christian Veillet, M. Rapaport, 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), Pôle Astronomie du LESIA, 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)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Pôle Planétologie du LESIA, 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)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and 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)
Subjects: Pluto, Atmosphere, Multidisciplinary, Planet, Nitrogen atmosphere, Astronomy, Light curve, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Occultation, Geology, Astrobiology
Abstract: Pluto's tenuous nitrogen atmosphere was first detected by the imprint left on the light curve of a star that was occulted by the planet in 1985 (ref. 1), and studied more extensively during a second occultation event in 1988 (refs 2-6). These events are, however, quite rare and Pluto's atmosphere remains poorly understood, as in particular the planet has not yet been visited by a spacecraft. Here we report data from the first occultations by Pluto since 1988. We find that, during the intervening 14 years, there seems to have been a doubling of the atmospheric pressure, a probable seasonal effect on Pluto.
Published: 2003

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