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16 results on '"Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL)"'

1. On the origin & thermal stability of Arrokoth's and Pluto's ices

Author

Marc Neveu, Harold A. Weaver, Mohamed Ramy El-Maarry, J. M. Parker, John R. Spencer, William B. McKinnon, Scott A. Sandford, Alissa M. Earle, Orkan M. Umurhan, Mihaly Horanyi, Ralph L. McNutt, G. R. Gladstone, Andrew F. Cheng, Catherine B. Olkin, R. P. Binzel, Y. J. Pendleton, Carey M. Lisse, Olivier Mousis, William M. Grundy, Jj Kavelaars, J. T. Keane, N. Dello-Russo, Wladimir Lyra, Jordan K. Steckloff, S. A. Stern, Ivan Linscott, Bernard Schmitt, H. A. Elliott, Leslie A. Young, Dale P. Cruikshank, Daniel T. Britt, B. L. Lewis, J. M. Moore, Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), Southwest Research Institute [Boulder] (SwRI), NASA Ames Research Center (ARC), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Southwest Research Institute [San Antonio] (SwRI), Department of Earth, Atmospheric and Planetary Sciences [MIT, Cambridge] (EAPS), Massachusetts Institute of Technology (MIT), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Physikalisches Institut [Bern], Universität Bern [Bern], Washington University in Saint Louis (WUSTL), Lowell Observatory [Flagstaff], 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), Centre National d'Etudes Spatiales (CNES), NASA for financial support of the New Horizons project, Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, and Universität Bern [Bern] (UNIBE)

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Physics, Solar System, 010504 meteorology & atmospheric sciences, Young stellar object, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Pluto, Outgassing, Stars, Supernova, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, 0103 physical sciences, Trans-Neptunian object, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics - Earth and Planetary Astrophysics, 0105 earth and related environmental sciences
Abstract

We discuss in a thermodynamic, geologically empirical way the long-term nature of the stable majority ices that could be present in Kuiper Belt Object 2014 MU69 after its 4.6 Gyr residence in the EKB as a cold classical object. Considering the stability versus sublimation into vacuum for the suite of ices commonly found on comets, Centaurs, and KBOs at the average ~40K sunlit surface temperature of MU69 over Myr to Gyr, we find only 3 common ices that are truly refractory: HCN, CH3OH, and H2O (in order of increasing stability). NH3 and H2CO ices are marginally stable and may be removed by any positive temperature excursions in the EKB, as produced every 1e8 - 1e9 yrs by nearby supernovae and passing O/B stars. To date the NH team has reported the presence of abundant CH3OH and evidence for H2O on MU69s surface (Lisse et al. 2017, Grundy et al. 2020). NH3 has been searched for, but not found. We predict that future absorption feature detections will be due to an HCN or poly-H2CO based species. Consideration of the conditions present in the EKB region during the formation era of MU69 lead us to infer that it formed "in the dark", in an optically thick mid-plane, unable to see the nascent, variable, highly luminous Young Stellar Object-TTauri Sun, and that KBOs contain HCN and CH3OH ice phases in addition to the H2O ice phases found in their Short Period comet descendants. Finally, when we apply our ice thermal stability analysis to bodies/populations related to MU69, we find that methanol ice may be ubiquitous in the outer solar system; that if Pluto is not a fully differentiated body, then it must have gained its hypervolatile ices from proto-planetary disk sources in the first few Myr of the solar systems existence; and that hypervolatile rich, highly primordial comet C/2016 R2 was placed onto an Oort Cloud orbit on a similar timescale., Comment: 34 Pages, 5 Figures, 2 SOM Tables

Published
2021

2. SuperCam calibration targets on board the perseverance rover: Fabrication and quantitative characterization

Author

Cousin, A., Sautter, V., Fabre, C., Dromart, G., Montagnac, G., Drouet, C., Meslin, P.Y., Gasnault, Olivier, Beyssac, O., Bernard, S., Cloutis, E., Forni, O., Beck, P., Fouchet, T., Johnson, J.R., Lasue, J., Ollila, A.M., de Parseval, P., Gouy, S., Caron, B., Madariaga, J.M., Arana, G., Madsen, M. Bo, Laserna, J., Moros, J., Manrique, J.A., Lopez-Reyes, G., Rull, F., Maurice, S., Wiens, R.C., Institut de recherche en astrophysique et planétologie (IRAP), 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), Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Géologie et gestion des ressources minérales et énergétiques (G2R), Université Henri Poincaré - Nancy 1 (UHP)-Institut National Polytechnique de Lorraine (INPL)-Centre de recherches sur la géologie des matières premières minérales et énergétiques (CREGU)-Centre National de la Recherche Scientifique (CNRS), Université de Lyon, Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), Institut Carnot Chimie Balard Cirimat, Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM), Université de Montpellier (UM), Dept. of Geography, University of Winnipeg, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, 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), Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), Los Alamos National Laboratory (LANL), Géosciences Environnement Toulouse (GET), Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Universidad del Pais Vasco / Euskal Herriko Unibertsitatea [Espagne] (UPV/EHU), Niels Bohr Institute [Copenhagen] (NBI), Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (UCPH)-University of Copenhagen = Københavns Universitet (UCPH), Universidad de Málaga [Málaga] = University of Málaga [Málaga], University of Valladolid, Unidad Asocida UVA-CSIC-CAB, University of Valladolid (UVA), Centre interuniversitaire de recherche et d'ingenierie des matériaux (CIRIMAT), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), Centre de microcaractérisation Raimond Castaing (Centre Castaing), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP)

Subjects
[SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology, LIBS, SuperCam, [SDU]Sciences of the Universe [physics], Mars2020, Mars, LIBS Contents, Perseverance, Instrumentation, Spectroscopy, Atomic and Molecular Physics, and Optics, Analytical Chemistry
Abstract

International audience; The Perseverance rover is exploring Jezero crater on Mars since February 2021. SuperCam instrument is part of the scientific payload, combining five different techniques in order to characterize the targets to sample: LIBS (Laser-Induced Breakdown Spectroscopy), Raman and Visible and Infrared (VISIR) spectroscopies, Sound Recording and a colored Imager. Thirty-six calibration targets have been developed for this instrument. Twenty-three of these calibration targets are dedicated to the LIBS technique, corresponding to rocks and/or minerals. Raman and VISIR spectroscopy have their own calibration targets but may also use the LIBS mineral targets as reference on Mars to test mineral detections. The choice and the fabrication of these calibration targets have been made in order to fulfill the science intents of the mission, as well as the technical and science intents of each of the SuperCam technique. These calibration targets have been spectrally characterized and they have shown to be chemically homogeneous at the SuperCam LIBS scale. Their elementary compositions are given, using two different quantitative methods. The composition of the calibration targets will be used as reference for future assessment of the quantitative capability of the SuperCam LIBS technique.

Published
2022

3. AIDA DART asteroid deflection test: Planetary defense and science objectives

Author

Eugene G. Fahnestock, Olivier S. Barnouin, Lance A. M. Benner, Cristina A. Thomas, Justin A. Atchison, Emma S.G. Rainey, Carolyn M. Ernst, Petr Pravec, Nancy L. Chabot, Andrew S. Rivkin, Angela Stickle, A. F. Cheng, Michael Kueppers, Derek C. Richardson, Patrick Michel, 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), Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), Operations Department (ESAC), European Space Astronomy Centre (ESAC), European Space Agency (ESA)-European Space Agency (ESA), Ondřejov Observatory of the Prague Astronomical Institute, and Czech Academy of Sciences [Prague] (CAS)

Subjects
Orbital speed, 010504 meteorology & atmospheric sciences, 01 natural sciences, law.invention, Telescope, Impact crater, Deflection (engineering), law, 0103 physical sciences, Aerospace engineering, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, computer.programming_language, [PHYS]Physics [physics], Dart, business.industry, Rendezvous, Astronomy and Astrophysics, Orbital period, Space and Planetary Science, Asteroid, Environmental science, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], business, computer
Abstract

The Asteroid Impact & Deflection Assessment (AIDA) mission is an international cooperation between NASA and ESA. NASA plans to provide the Double Asteroid Redirection Test (DART) mission which will perform a kinetic impactor experiment to demonstrate asteroid impact hazard mitigation. ESA proposes to provide the Hera mission which will rendezvous with the target to monitor the deflection, perform detailed characterizations, and measure the DART impact outcomes and momentum transfer efficiency. The primary goals of AIDA are (i) to demonstrate the kinetic impact technique on a potentially hazardous near-Earth asteroid and (ii) to measure and characterize the deflection caused by the impact. The AIDA target will be the binary asteroid (65803) Didymos, which is of spectral type Sq, with the deflection experiment to occur in October, 2022. The DART impact on the secondary member of the binary at ∼6 km/s changes the orbital speed and the binary orbit period, which can be measured by Earth-based observatories with telescope apertures as small as 1 m. The DART impact will in addition alter the orbital and rotational states of the Didymos binary, leading to excitation of eccentricity and libration that, if measured by Hera, can constrain internal structure of the target asteroid. Measurements of the DART crater diameter and morphology can constrain target properties like cohesion and porosity based on numerical simulations of the DART impact.

Published
2018

4. The nitrogen cycles on Pluto over seasonal and astronomical timescales

Author

Orkan M. Umurhan, Tanguy Bertrand, Paul M. Schenk, Harold A. Weaver, Catherine B. Olkin, Oliver L. White, Bernard Schmitt, Leslie A. Young, Silvia Protopapa, Kimberly Ennico, François Forget, Alan Stern, William M. Grundy, Kelsi N. Singer, Amanda M. Zangari, 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), NASA Ames Research Center (ARC), Lowell Observatory [Flagstaff], Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Southwest Research Institute [Boulder] (SwRI), Lunar and Planetary Institute [Houston] (LPI), and Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL)

Subjects
Sputnik Planitia, 010504 meteorology & atmospheric sciences, Nitrogen, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Structural basin, 01 natural sciences, Latitude, Longitude of the periapsis, Paleo Modeling, Paleontology, ices, 0103 physical sciences, Glacial period, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, geography, geography.geographical_feature_category, Pluto, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Astronomy and Astrophysics, Glacier, GCM, 13. Climate action, Space and Planetary Science, Sublimation (phase transition), Ice sheet, Geology
Abstract

International audience; Pluto’s landscape is shaped by the endless condensation and sublimation cycles of the volatile ices covering its surface. In particular, the Sputnik Planitia ice sheet, which is thought to be the main reservoir of nitrogen ice, displays a large diversity of terrains, with bright and dark plains, small pits and troughs, topographic depressions and evidences of recent and past glacial flows. Outside Sputnik Planitia, New Horizons also revealed numerous nitrogen ice deposits, in the eastern side of Tombaugh Regio and at mid-northern latitudes.These observations suggest a complex history involving volatile and glacial processes occurring on different timescales. We present numerical simulations of volatile transport on Pluto performed with a model designed to simulate the nitrogen cycle over millions of years, taking into account the changes of obliquity, solar longitude of perihelion and eccentricity as experienced by Pluto. Using this model, we first explore how the volatile and glacial activity of nitrogen within Sputnik Planitia has been impacted by the diurnal, seasonal and astronomical cycles of Pluto. Results show that the obliquity dominates the N 2 cycle and that over one obliquity cycle, the latitudes of Sputnik Planitia between 25 °S-30 °N are dom- inated by N 2 condensation, while the northern regions between 30 °N and -50 °N are dominated by N 2 sublimation. We find that a net amount of 1 km of ice has sublimed at the northern edge of Sputnik Planitia during the last 2 millions of years. It must have been compensated by a viscous flow of the thick ice sheet. By comparing these results with the observed geology of Sputnik Planitia, we can relate the formation of the small pits and the brightness of the ice at the center of Sputnik Planitia to the subli- mation and condensation of ice occurring at the annual timescale, while the glacial flows at its eastern edge and the erosion of the water ice mountains all around the ice sheet are instead related to the as- tronomical timescale. We also perform simulations including a glacial flow scheme which shows that the Sputnik Planitia ice sheet is currently at its minimum extent at the northern and southern edges. We also explore the stability of N 2 ice deposits outside the latitudes and longitudes of the Sputnik Planitia basin. Results show that N 2 ice is not stable at the poles but rather in the equatorial regions, in particu- lar in depressions, where thick deposits may persist over tens of millions of years, before being trapped in Sputnik Planitia. Finally, another key result is that the minimum and maximum surface pressures ob- tained over the simulated millions of years remain in the range of milli-Pascals and Pascals, respectively. This suggests that Pluto never encountered conditions allowing liquid nitrogen to flow directly on its sur- face. Instead, we suggest that the numerous geomorphological evidences of past liquid flow observed on Pluto’s surface are the result of liquid nitrogen that flowed at the base of thick ancient nitrogen glaciers, which have since disappeared.

Published
2018

5. Scattering by whistler-mode waves during a quiet period perturbed by substorm activity

Author

David Hartley, S. A. Thaller, Ondřej Santolík, Michael H. Denton, Jean-Francois Ripoll, V. Loridan, Drew Turner, Michael G. Henderson, William S. Kurth, A. Y. Ukhorskiy, David M. Malaspina, J. F. Fennell, Geoff Reeves, G. S. Cunningham, Craig Kletzing, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Space Science Institute [Boulder] (SSI), Department of Physics and Astronomy [Iowa City], University of Iowa [Iowa City], Los Alamos National Laboratory (LANL), Department of Astrophysical and Planetary Sciences [Boulder], University of Colorado [Boulder], Laboratory for Atmospheric and Space Physics [Boulder] (LASP), Faculty of Mathematics and Physics [Charles University of Praha], Charles University [Prague] (CU), Institute of Atmospheric Physics [Prague] (IAP), Czech Academy of Sciences [Prague] (CAS), DPHY, ONERA, Université Paris Saclay [Palaiseau], ONERA-Université Paris-Saclay, The Aerospace Corporation, Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), and This work was performed under the auspices of an agreement between CEA/DAM and NNSA/DP on cooperation on fundamental science. The authors acknowledge the International Space Sciences Institute (ISSI) and the participants in a 2020 ISSI workshop. Part of the research presented in this article was supported by the Laboratory Directed Research and Development program of Los Alamos National Laboratory under project number 20180731ER. Work at Iowa is performed under the support of JHU/APL contract 921647 under NASA Prime contract NAS5-01072. Work at CU/LASP is supported by NASA grant 80NSSC18K1034. O.S. acknowledges support from the Czech Academy of Sciences Praemium Academiae award and from the MEYS grant LTAUSA17070. Processing and analysis of the [HOPE, MagEIS, REPT, or ECT] data was supported by Energetic Particle, Composition, and Thermal Plasma (RBSP-ECT) investigation funded under NASA's Prime contract no. NAS5-01072. All RBSP-ECT data are publicly available at the Web site http://www.RBSP-ect.lanl.gov

Subjects
Atmospheric Science, 010504 meteorology & atmospheric sciences, Plasmasphere, Electron, 01 natural sciences, [SPI]Engineering Sciences [physics], symbols.namesake, 0103 physical sciences, Substorm, Van Allen Probes, Pitch angle, Diffusion (business), 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, [PHYS]Physics [physics], Physics, Scattering, Whistler-mode waves, Radiation belts, Computational physics, Geophysics, Amplitude, Moderate substorm activity, Wave-particle interactions, Space and Planetary Science, Van Allen radiation belt, Physics::Space Physics, symbols
Abstract

International audience; We study the dynamics of radiation belt electrons during a 10-day quiet period perturbed by substorm activity and preceding a high-speed stream (HSS), aiming at a global description of the radiation belts in L-shell, L in [2, 6], and energy [0.1, 10] MeV. We combine Van Allen Probes observations and Fokker-Planck numerical simulations of pitch-angle diffusion. The Fokker-Planck model uses event-driven pitch angle diffusion coefficients from whistler-mode waves, built from the wave properties and the ambient plasma density measurements from the Van Allen Probes. We first find this event has some similar characteristics to regular quiet times previously studied; a widely extended plasmasphere within which we observe strong and varying whistler-mode waves. These ambient conditions lead to strong pitch-angle scattering, which contributes to the creation of a wide slot region as well as a significant decay of the outer radiation belts, which are observed and qualitatively well simulated. In addition, we find the substorm activity causes short duration (within ± 4h) decay of the plasma density and a lowering amplitude of the whistler-mode waves within the plasmasphere, both causing opposite effects in terms of pitch angle diffusion. This leads to a diminution of pitch-angle diffusion at the time of the main substorm activity. Conversely, whistler-mode waves become enhanced in the time periods between the substorm injections. All effects cumulated, we find an enhancement of pitch angle diffusion by whistler-mode waves above L~4.7 during the 10-day period. This directly relates to the combination of quietness and substorm activity which allows pitch angle diffusing of up to 1 MeV electrons in the outer belt. Relativistic electrons of 1–2 MeV remain trapped in the outer belt, from L~4.7 to L~5.2, forming, in both the observations and the simulations, a distinct pocket of remnant electrons.

Published
2021

6. Global compositional cartography of Pluto from intensity-based registration of LEISA data

Author

Tanguy Bertrand, Catherine B. Olkin, Kimberly Ennico, John R. Spencer, Harold A. Weaver, L. Gabasova, S. A. Stern, Bernard Schmitt, William M. Grundy, Leslie A. Young, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), Lowell Observatory [Flagstaff], NASA Ames Research Center (ARC), Southwest Research Institute [Boulder] (SwRI), and Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL)

Subjects
New horizons, 010504 meteorology & atmospheric sciences, Ices, Multispectral image, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Terrain, 01 natural sciences, Latitude, New Horizons, Image processing, 0103 physical sciences, surface, 010303 astronomy & astrophysics, Geomorphology, 0105 earth and related environmental sciences, Pluto, Spacecraft, business.industry, Hyperspectral imaging, Astronomy and Astrophysics, IR spectroscopy, 13. Climate action, Space and Planetary Science, business, Intensity (heat transfer), Geology
Abstract

In 2015 the New Horizons spacecraft reached the Pluto system and returned unprecedentedly detailed measurements of its surface properties. These measurements have already been integrated into global reflectance, topography and narrow-band multispectral surface maps. However, analysis of the hyperspectral data from the Ralph/LEISA infrared spectrometer, which lets us analyse the surface composition, has until now been confined to the high-resolution encounter hemisphere of Pluto. We use an innovative technique — intensity-based registration — to co-register this high-resolution data with lower-resolution measurements taken during the spacecraft’s approach, and present the first global qualitative composition maps for CH 4 , N 2 and H 2 O ice, and a tholin-like red material. We compare these maps with the other maps produced for Pluto and study the global extent of the previously-described latitudinal distribution of the surface components, which is relatively longitudinally constant with the exception of Sputnik Planitia. We also correlate these compositional components with geological features and propose physical interpretations, which include: CH 4 -ice-rich dissected plateaus in high northern latitudes, CH 4 -rich eroded terrain with N 2 -rich infill in medium northern latitudes, CH 4 -rich bladed terrain in low northern latitudes, and a red material belt overlaying H 2 O ice in low southern latitudes.

Published
2021

7. Schumann resonance on Titan: A critical Re-assessment

Author

Alice Le Gall, Ralph D. Lorenz, Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), 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), Institut Universitaire de France (IUF), and Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.)

Subjects
Physics, 010504 meteorology & atmospheric sciences, Schumann resonances, Magnetosphere, Astronomy and Astrophysics, Geophysics, 01 natural sciences, symbols.namesake, Ionospheres, Radio observations, [SDU]Sciences of the Universe [physics], 13. Climate action, Space and Planetary Science, Normal mode, Electric field, 0103 physical sciences, symbols, Extremely low frequency, Ionosphere, Titan, Titan (rocket family), 010303 astronomy & astrophysics, Excitation, 0105 earth and related environmental sciences
Abstract

International audience; Extremely Low Frequency (ELF) electric field signals recorded by the Huygens probe have previously been interpreted as indicating a Schumann Resonance (SR) in the ionosphere-ocean cavity. This interpretation required accommodation of a number of anomalous features with respect to the terrestrial SR, namely a lack of observed lightning discharges with instead an appeal to excitation by interaction with the Saturnian magnetosphere, a horizontal field orientation, and the presence of only a single spectral peak speculated to be the second eigenmode. We suggest here that the data are dominated by artifacts due to mechanical oscillations of the booms or other elements of the probe. Although such an explanation was previously dismissed, we show in new analyses that the ELF time series correlates closely with the history of other mechanical vibration on the probe. In particular, the growth of the ‘ELF’ signals after the release of the main parachute, when the most extensive probe motions also began, and the disappearance of the signals within a few seconds after probe impact, point to a mechanical origin. We additionally review the capability of possible future SR measurements to constrain the thickness of an ice crust on Titan. Even if the magnetospheric excitation does not happen (it may or may not have occurred during the Huygens descent, we only argue that it is not required to explain the data), sporadic lightning during methane rainstorms could yet occur and excite occasional SR activity. However, the interpretation of the SR to retrieve ice thickness is challenged by ambiguities without simultaneous knowledge of the lower ionospheric structure.

Published
2020

8. Nature, distribution, and origin of Titan’s Undifferentiated Plains

Author

Alexander G. Hayes, Kenneth J. Lawrence, Athena Coustenis, Michael Malaska, A. Le Gall, M. A. Janssen, A. Solomonidou, Ellen R. Stofan, Samuel Birch, Jani Radebaugh, Bryan Stiles, Catherine D. Neish, R. L. Kirk, Elizabeth P. Turtle, K. L. Mitchell, Ashley Schoenfeld, Rosaly M. C. Lopes, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Physics and Space Sciences [FIT], Florida Institute of Technology [Melbourne], Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), Department of Astronomy [Ithaca], Cornell University [New York], Department of Geological Sciences [BYU], Brigham Young University (BYU), Astrogeology Science Center [Flagstaff], United States Geological Survey [Reston] (USGS), Department of Earth and Planetary Sciences [UCL/Birkbeck], Birkbeck College [University of London], and California Institute of Technology (CALTECH)-NASA

Subjects
Synthetic aperture radar, 010504 meteorology & atmospheric sciences, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Fluvial, 01 natural sciences, Astrobiology, law.invention, Sedimentary depositional environment, Paleontology, symbols.namesake, Impact crater, law, 0103 physical sciences, Radar, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Astronomy and Astrophysics, 15. Life on land, Radar observations, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], 13. Climate action, Space and Planetary Science, symbols, Aeolian processes, Cassini, Sedimentary rock, Geological processes, Titan, Titan (rocket family), Geology
Abstract

The Undifferentiated Plains on Titan, first mapped by Lopes et al. (Lopes, R.M.C. et al., 2010. Icarus, 205, 540–588), are vast expanses of terrains that appear radar-dark and fairly uniform in Cassini Synthetic Aperture Radar (SAR) images. As a result, these terrains are often referred to as “blandlands”. While the interpretation of several other geologic units on Titan – such as dunes, lakes, and well-preserved impact craters – has been relatively straightforward, the origin of the Undifferentiated Plains has remained elusive. SAR images show that these “blandlands” are mostly found at mid-latitudes and appear relatively featureless at radar wavelengths, with no major topographic features. Their gradational boundaries and paucity of recognizable features in SAR data make geologic interpretation particularly challenging. We have mapped the distribution of these terrains using SAR swaths up to flyby T92 (July 2013), which cover >50% of Titan’s surface. We compared SAR images with other data sets where available, including topography derived from the SARTopo method and stereo DEMs, the response from RADAR radiometry, hyperspectral imaging data from Cassini’s Visual and Infrared Mapping Spectrometer (VIMS), and near infrared imaging from the Imaging Science Subsystem (ISS). We examined and evaluated different formation mechanisms, including (i) cryovolcanic origin, consisting of overlapping flows of low relief or (ii) sedimentary origins, resulting from fluvial/lacustrine or aeolian deposition, or accumulation of photolysis products created in the atmosphere. Our analysis indicates that the Undifferentiated Plains unit is consistent with a composition predominantly containing organic rather than icy materials and formed by depositional and/or sedimentary processes. We conclude that aeolian processes played a major part in the formation of the Undifferentiated Plains; however, other processes (fluvial, deposition of photolysis products) are likely to have contributed, possibly in differing proportions depending on location.

Published
2016

9. ChemCam passive reflectance spectroscopy of surface materials at the Curiosity landing site, Mars

Author

Johnson, Jeffrey R., Bell, J.F., Bender, S., Blaney, D., Cloutis, E., DeFlores, L., Ehlmann, B., Gasnault, O., Gondet, B., Kinch, K., Lemmon, M., Le Mouélic, S., Maurice, S., Rice, M., Wiens, R.C. and the MSL Science Team, DLR Collaborator (MSL Science Team), Reitz G., Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), ASU, Planetary Science Institute [Tucson] (PSI), Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Department of Geography [Winnipeg], University of Winnipeg, Division of Geological and Planetary Sciences [Pasadena], California Institute of Technology (CALTECH), 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), 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), Department of Atmospheric Sciences [College Station], Texas A&M University [College Station], 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), and Los Alamos National Laboratory (LANL)

Subjects
Martian, 010504 meteorology & atmospheric sciences, Spectrometer, Mars, Astronomy and Astrophysics, Mars Exploration Program, Hematite, 01 natural sciences, [SDU]Sciences of the Universe [physics], 13. Climate action, Space and Planetary Science, visual_art, Martian surface, 0103 physical sciences, Radiance, visual_art.visual_art_medium, Calibration, surface, Absorption (electromagnetic radiation), 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Spectroscopy, Geology, 0105 earth and related environmental sciences, Remote sensing
Abstract

The spectrometers on the Mars Science Laboratory (MSL) ChemCam instrument were used in passive mode to record visible/near-infrared (400–840 nm) radiance from the martian surface. Using the onboard ChemCam calibration targets’ housing as a reflectance standard, we developed methods to collect, calibrate, and reduce radiance observations to relative reflectance. Such measurements accurately reproduce the known reflectance spectra of other calibration targets on the rover, and represent the highest spatial resolution (0.65 mrad) and spectral sampling (

Published
2015

10. MarcoPolo-R: Near-Earth Asteroid sample return mission selected for the assessment study phase of the ESA program cosmic vision

Author

L. M. Lara, M. A. Barucci, Hermann Böhnhardt, Simon F. Green, Andrew F. Cheng, John Robert Brucato, Detlef Koschny, Pascale Ehrenfreund, Patrick Michel, Bernard Marty, D. Agnolon, E. Dotto, Ian A. Franchi, Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA), 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), Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, INAF - Osservatorio Astrofisico di Arcetri (OAA), Istituto Nazionale di Astrofisica (INAF), INAF - Osservatorio Astronomico di Roma (OAR), Leiden Observatory [Leiden], Universiteit Leiden [Leiden], The Open University [Milton Keynes] (OU), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Centre de Recherches Pétrographiques et Géochimiques (CRPG), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), European Space Agency Advanced Concepts and Science Payloads Office (ESA ESTEC), European Space Agency (ESA), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Universiteit Leiden, and Agence Spatiale Européenne = European Space Agency (ESA)

Subjects
Sample return mission, Cosmic Vision, 010504 meteorology & atmospheric sciences, Primitive material, Population, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Aerospace Engineering, Context (language use), 01 natural sciences, Astrobiology, Origin, Near-Earth Asteroid, 0103 physical sciences, education, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, education.field_of_study, Near-Earth object, Planetary habitability, Potentially hazardous object, Astronomy, Re-entry capsule, 13. Climate action, Asteroid, Geology
Abstract

International audience; This paper presents the sample return mission to a primitive Near-Earth Asteroid (NEA) MarcoPolo-R proposed to the European Space Agency in December 2010. MarcoPolo-R was selected in February 2011 with three other missions addressing different science objectives for the two-year Assessment Phase of the Medium-Class mission competition of the Cosmic Vision 2 program for launch in 2022. The baseline target of MarcoPolo-R is the binary NEA (175706) 1996 FG3, which offers an efficient operational and technical mission profile. A binary target also provides enhanced science return. The choice of a binary target allows several scientific investigations to occur more easily than through a single object, in particular regarding the fascinating geology and geophysics of asteroids. MarcoPolo-R will rendezvous with a primitive, organic-rich NEA, scientifically characterize it at multiple scales, and return a bulk sample to Earth for laboratory analyses. The MarcoPolo-R sample will provide a representative sample from the surface of a known asteroid with known geologic context, and will contribute to the inventory of primitive material that is probably missing from the meteorite collection. The MarcoPolo-R samples will thus contribute to the exploration of the origin of planetary materials and initial stages of habitable planet formation, to the identification and characterization of the organics and volatiles in a primitive asteroid and to the understanding of the unique geomorphology, dynamics and evolution of a binary asteroid that belongs to the Potentially Hazardous Asteroid (PHA) population.

Published
2014

11. First detection of Mars atmospheric hydroxyl: CRISM Near-IR measurement versus LMD GCM simulation of OH Meinel band emission in the Mars polar winter atmosphere

Author

Michael J. Wolff, H. Nair, Antonio Garcia-Munoz, Scott L. Murchie, Franck Montmessin, Brad J. Sandor, R. Todd Clancy, Franck Lefèvre, Michael D. Smith, Space Science Institute [Boulder] (SSI), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), NASA Goddard Space Flight Center (GSFC), Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), and Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA)

Subjects
010504 meteorology & atmospheric sciences, Photochemistry, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Population, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Analytical chemistry, Mars, Atmospheric sciences, 01 natural sciences, 7. Clean energy, Mesosphere, Atmosphere, 0103 physical sciences, education, 010303 astronomy & astrophysics, Spectroscopy, 0105 earth and related environmental sciences, Physics, education.field_of_study, Aeronomy, Airglow, Astronomy and Astrophysics, Mars Exploration Program, Atmosphere of Mars, Dynamics, CRISM, 13. Climate action, Space and Planetary Science
Abstract

Visible and near-IR Meinel band emissions originate from excited OH in the terrestrial upper atmosphere (Meinel, I.A.B. [1950]. Astrophys. J. 111, 555. http://dx.doi.org/10.1086/145296 ), and have recently been detected in the Venus nightside upper mesosphere (Piccioni, G. et al. [2008]. Astron. Astrophys. 483, L29–L33. http://dx.doi.org/10.1051/0004-6361:200809761 ). Meinel band observations support key studies of transport and photochemistry in both of these atmospheres. In the case of Mars, OH regulates the basic stability of the CO2 atmosphere to photolytic decomposition (to CO and O2, e.g. Parkinson, T.D., Hunten, D.M. [1972]. J. Atmos. Sci. 29, 1380–1390. http://dx.doi.org/10.1175/1520-0469(1972)029 2.0.CO;2 ), and yet has never been measured. We present the first detection of Mars atmospheric OH, associated with CRISM near-IR spectral limb observations of polar night Meinel band emissions centered at 1.45 and 2.9 μm. Meinel band (1–0), (2–1), and (2–0) average limb intensities of 990 ± 280, 1060 ± 480, and 200 ± 100 kiloRayleighs (kR), respectively, are determined for 70–90 NS polar winter latitudes over altitudes of 40–56 km. Additional OH bands, such as (3–2), (3–1), and (4–2), present ⩽1σ measurements. Uncertainty in the (4–2) band emission rate contributes to increased uncertainty in the determination of the O2(1Δg) (0–0)/(0–1) band emission ratio A 00 / A 01 = 47 - 12 + 26 . An average profile retrieval for Mars OH polar nightglow indicates 45–55 km altitude levels for volume emission rates (VER) of 0.4 (2–0) to 2 (1–0, 2–1) × 104 photons/(cm3 s). Similar to polar night O2(1Δg) emission (e.g. Clancy, R.T. et al. [2012]. J. Geophys. Res. (Planets) 117, E00J10. http://dx.doi.org/10.1029/2011JE004018 ), Meinel OH band emission is supported by upper level, winter poleward transport of O and H in the deep Hadley solsticial circulations of Mars. The retrieved OH emission rates are compared to polar winter OH nightglow simulated by the LMD (Laboratoire de Meteorologie Dynamique) photochemical GCM (global climate model), employing detailed photochemistry (e.g. Lefevre, F., Lebonnois, S., Montmessin, F., Forget, F. [2004]. J. Geophys. Res. (Planets) 109, E07004. http://dx.doi.org/10.1029/2004JE002268 ) and energy transfer processes (excitation and quenching) developed for Mars Meinel OH band nightglow by Garcia Munoz et al. (Garcia Munoz, A., McConnell, J.C., McDade, I.C., Melo, S.M.L. [2005]. Icarus 176, 75–95). Modeled versus observed OH emission behavior agrees within measurement uncertainties with the assumptions of a Bates–Nicolet (H + O3) source for excited OH production, and ‘collisional-cascade’ quenching of the OH vibrational population by CO2. ‘Sudden-death’ quenching of excited OH by CO2 leads to 100× less OH emission than observed. The combined agreement between LMD GCM simulated and CRISM observed O2(1Δg) and Meinel OH polar nightglow behaviors represents a significant demonstration of the LMD model capability to couple odd oxygen and hydrogen photochemistry and transport by the Mars global circulation in a realistic fashion.

Published
2013

12. The NEO (175706) 1996 FG3 in the 2–4μm spectral region: Evidence for an aqueously altered surface

Author

Andrew S. Rivkin, Ronald J. Vervack, Ellen S. Howell, Yan Fernandez, Michael C. Nolan, C. Magri, Andrew F. Cheng, M. Antonietta Barucci, Patrick Michel, Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), Economics, University of Hull, 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), De la Préhistoire à l'Actuel : Culture, Environnement et Anthropologie (PACEA), and Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS]Physics [physics], Materials science, 010504 meteorology & atmospheric sciences, Infrared telescope, Astronomy, Astronomy and Astrophysics, 01 natural sciences, Space and Planetary Science, Asteroid, Absorption band, 0103 physical sciences, Optical surface, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Spectroscopy, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

We present observations of the binary near-Earth Asteroid (175706) 1996 FG3 in the 2–4 μm spectral region, obtained on multiple nights using the SpeX instrument on the NASA Infrared Telescope Facility (IRTF). We find evidence for an absorption band of ∼5–10% (depending on the night and details of continuum choice), diagnostic for hydrated/hydroxylated minerals on the asteroid surface. This demonstrates that the optical surface of 1996 FG3 has not been heated to dehydrating temperatures. Sample-return missions targeting 1996 FG3 will likely find relatively fresh areas for sampling.

Published
2013

13. Transient surface liquid in Titan’s polar regions from Cassini

Author

THE CASSINI RADAR TEAM, HAYES, A. G., AHARONSON, O., LUNINE, J.I., KIRK, R. L., ZEBKER, H. A., WYE, L. C., LORENZ, R. D., TURTLE, E. P., PAILLOU, Philippe, MITRI, G., WALL, S. D., STOFAN, E. R., MITCHELL, K. L., ELACHI, C., Division of Geological and Planetary Sciences [Pasadena], California Institute of Technology (CALTECH), Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, US Geological Survey [Flagstaff], United States Geological Survey [Reston] (USGS), Department of Electrical Engineering [Stanford], Stanford University, Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), 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), 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), Université Sciences et Technologies - Bordeaux 1, Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), and Proxemy Research Inc

Subjects
Shore, geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Atmospheric circulation, Climate oscillation, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astronomy and Astrophysics, Atmospheric sciences, 01 natural sciences, symbols.namesake, 13. Climate action, Space and Planetary Science, Radar imaging, 0103 physical sciences, symbols, Polar, Exponential decay, Water cycle, Titan (rocket family), 010303 astronomy & astrophysics, Geology, 0105 earth and related environmental sciences
Abstract

International audience; Cassini RADAR images of Titan's south polar region acquired during southern summer contain lake features which disappear between observations. These features show a tenfold increases in backscatter cross-section between images acquired one year apart, which is inconsistent with common scattering models without invoking temporal variability. The morphologic boundaries are transient, further supporting changes in lake level. These observations are consistent with the exposure of diffusely scattering lakebeds that were previously hidden by an attenuating liquid medium. We use a two-layer model to explain backscatter variations and estimate a drop in liquid depth of approximately 1-m-per-year. On larger scales, we observe shoreline recession between ISS and RADAR images of Ontario Lacus, the largest lake in Titan's south polar region. The recession, occurring between June 2005 and July 2009, is inversely proportional to slopes estimated from altimetric profiles and the exponential decay of near-shore backscatter, consistent with a uniform reduction of 4 ± 1.3 m in lake depth.Of the potential explanations for observed surface changes, we favor evaporation and infiltration. The disappearance of dark features and the recession of Ontario's shoreline represents volatile transport in an active methane-based hydrologic cycle. Observed loss rates are compared and shown to be consistent with available global circulation models. To date, no unambiguous changes in lake level have been observed between repeat images in the north polar region, although further investigation is warranted. These observations constrain volatile flux rates in Titan's hydrologic system and demonstrate that the surface plays an active role in its evolution. Constraining these seasonal changes represents the first step toward our understanding of longer climate cycles that may determine liquid distribution on Titan over orbital time periods.

Published
2011

14. Radar-bright channels on Titan

Author

Philippe Paillou, M. A. Janssen, S. D. Wall, A. Le Gall, Ralph D. Lorenz, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), SSE 2010, 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)-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), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-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)-Université de Bordeaux (UB), and Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL)

Subjects
Synthetic aperture radar, Brightness, 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Scattering, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astronomy and Astrophysics, Polarization (waves), 01 natural sciences, Debris, Space-based radar, law.invention, Radar astronomy, Space and Planetary Science, law, 0103 physical sciences, Radar, 010303 astronomy & astrophysics, Geology, 0105 earth and related environmental sciences, Remote sensing
Abstract

International audience; During Cassini's T44 flyby of Titan (May 28, 2008), the Cassini SAR (synthetic aperture radar) revealed sinuous channels in the Southwest of Xanadu. These channels feature very large radar cross-sections, up to 5 dB, whereas the angle of incidence was relatively high, ˜20°. This backscatter is larger than allowed by the coherent backscatter model considered to explain the unusual reflective and polarization properties of the icy satellites and only a few radar scattering mechanisms can be responsible for such high radar returns. The presence of rounded (icy) pebbles with size larger than the radar wavelength (2.18 cm) is proposed to explain the large radar cross-sections measured in these units. The radar-bright channels are thus interpreted as riverbeds, where debris, likely shaped and transported by fluvial activity, have been deposited. Similar debris were observed in the landing site of the Huygens probe. This work may point the way to an explanation for the enhanced brightness of other fluvial regions of Titan.

Published
2010

15. Distribution and properties of fragments and debris from the split Comet 73P/Schwassmann-Wachmann 3 as revealed by Spitzer Space Telescope

Author

Mark V. Sykes, William T. Reach, Jeremie Vaubaillon, Michael S. P. Kelley, Carey M. Lisse, Infrared Processing and Analysis Center (IPAC), California Institute of Technology (CALTECH), 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 Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Department of Physics [Orlando] (UCF | Physics), University of Central Florida [Orlando] (UCF), Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), Planetary Science Institute [Tucson] (PSI), Infrared Processing and Analysis Center [MS 220-6], Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)

Subjects
Solar System, Meteors, 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Infrared, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, Spitzer Space Telescope, 0103 physical sciences, Comets, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Infrared observations, Meteoroid, Astronomy, Astronomy and Astrophysics, Astrometry, Radiation pressure, 13. Climate action, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Earth and Planetary Astrophysics, Dimensionless quantity
Abstract

During 2006 Mar - 2007 Jan, we used the IRAC and MIPS instruments on the Spitzer Space Telescope to study the infrared emission from the ensemble of fragments, meteoroids, and dust tails in the more than 3 degree wide 73P/Schwassmann-Wachmann 3 debris field. We also investigated contemporaneous ground based and HST observations. In 2006 May, 55 fragments were detected in the Spitzer image. The wide spread of fragments along the comet's orbit indicates they were formed from the 1995 splitting event. While the number of major fragments in the Spitzer image is similar to that seen from the ground by optical observers, the correspondence between the fragments with optical astrometry and those seen in the Spitzer images cannot be readily established, due either to strong non-gravitational terms, astrometric uncertainties, or transience of the fragments outgassing. The Spitzer data resolve the structure of the dust comae at a resolution of 1000 km, and they reveal the infrared emission due to large (mm to cm size) particles in a continuous dust trail that closely follows the projected orbit. We detect fluorescence from outflowing CO2 gas from the largest fragments (B and C), and we measure the CO2:H2O proportion (1:10 and 1:20, respectively). Three dimensionless parameters to explain dynamics of the solid particles: alpha (sublimation reaction), beta (radiation pressure), and nu (ejection velocity). The major fragments have nu>alpha>beta and are dominated by the kinetic energy imparted to them by the fragmentation process. The small, ephemeral fragments seen by HST in the tails of the major fragments have alpha>nu>beta dominated by rocket forces. The meteoroids along the projected orbit have beta~nu>>alpha. Dust in the fragments' tails has beta>>(nu+alpha) and is dominated by radiation pressure., accepted 5/13/09 by Icarus

Published
2009

16. Speed of sound measurements and the methane abundance in Titan's atmosphere

Author

B. Hathi, Philip D. Rosenberg, Mark Leese, Håkan Svedhem, John C. Zarnecki, Axel Hagermann, Martin C. Towner, Ralph D. Lorenz, James Garry, University of Arizona, and Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL)

Subjects
Astronomy and Astrophysics, Atmospheric sciences, Methane, symbols.namesake, chemistry.chemical_compound, chemistry, Space and Planetary Science, Speed of sound, Physical Sciences, Scale variation, symbols, Environmental science, Titan (rocket family), ComputingMilieux_MISCELLANEOUS
Abstract

Aboard the Huygens probe, which descended through Titan's atmosphere in January 2005, was the Surface Science Package (SSP), a set of 9 sensors, including a speed-of-sound sensor. We present the first detailed description of the SSP speed of sound measurements and report constraints on the methane content in Titan's lower atmosphere based on these measurements. After a careful calibration and subsequent Bayesian analysis, our measurements yield a most likely methane fraction in Titan's lower atmosphere of approximately 2% at 10 km, increasing to 3.5% at lower altitudes, based on a binary composition. Our data show that any large scale variation of methane within the lower 11 km of Titan's atmosphere is unlikely. Within experimental and theoretical uncertainties, our results are compatible with earlier estimates obtained from the GCMS experiment [Niemann, H.B., Atreya, S.K., Bauer, S.J., Carignan, G.R., Demick, J.E., Frost, R.L., Gautier, D., Haberman, J.A., Harpold, D.N., Hunten, D.M., Israel, G., Lunine, J.I., Kasprzak, W.T., Owen, T.C., Paulkovich, M., Raulin, F., Raaen, E., Way, S.H., 2005. Nature 438 (7069), 779–784].

Published
2007

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