Search Publications
Composition of Titan's lower atmosphere and simple surface volatiles as measured by the Cassini-Huygens probe gas chromatograph mass spectrometer experiment
Atreya, S. K.; Lunine, J. I.; Kasprzak, W. T. +7 more
The Cassini-Huygens probe gas chromatograph mass spectrometer (GCMS) determined the composition of the Titan atmosphere from ∼140 km altitude to the surface. After landing, it returned composition data of gases evaporated from the surface. Height profiles of molecular nitrogen (N2), methane (CH4), and molecular hydrogen (H
Depth of the Martian cryosphere: Revised estimates and implications for the existence and detection of subpermafrost groundwater
Heggy, Essam; Clifford, Stephen M.; Lasue, Jeremie +3 more
The Martian cryosphere is defined as that region of the crust where the temperature remains continuously below the freezing point of water. Previous estimates of its present thickness have ranged from ∼2.3-4.7 km at the equator to ∼6.5-12.5 km at the poles. Here we revisit these calculations, review some of the assumptions on which they were based…
Superrotation of Venus' atmosphere analyzed with a full general circulation model
Lebonnois, Sébastien; Hourdin, Frédéric; Eymet, Vincent +3 more
A general circulation model (GCM) has been developed for the Venus atmosphere, from the surface up to 100 km altitude, based on the GCM developed for Earth at our laboratory. Key features of this new GCM include topography, diurnal cycle, dependence of the specific heat on temperature, and a consistent radiative transfer module based on net exchan…
Detection and mapping of hydrocarbon deposits on Titan
Nicholson, Philip D.; Sotin, Christophe; Barnes, Jason W. +13 more
We report the identification of compounds on Titan's surface by spatially resolved imaging spectroscopy methods through Titan's atmosphere, and set upper limits to other organic compounds. We present evidence for surface deposits of solid benzene (C6H6), solid and/or liquid ethane (C2H6), or methane (CH<…
Mineralogy and stratigraphy of phyllosilicate-bearing and dark mantling units in the greater Mawrth Vallis/west Arabia Terra area: Constraints on geological origin
Bibring, J. -P.; Poulet, F.; Bishop, J. L. +13 more
Analyses of MRO/CRISM images of the greater Mawrth Vallis region of Mars affirm the presence of two primary phyllosilicate assemblages throughout a region ∼1000 × 1000 km. These two units consist of an Fe/Mg-phyllosilicate assemblage overlain by an Al-phyllosilicate and hydrated silica assemblage. The lower unit contains Fe/Mg-smectites, sometimes…
Water ice at low to midlatitudes on Mars
Mustard, John; Forget, François; Vincendon, Mathieu
In this paper, we analyze water ice occurrences at the surface of Mars using near-infrared observations, and we study their distribution with a climate model. Latitudes between 45°S and 50°N are considered. Data from the Observatoire pour la Minéralogie, l'Eau, les Glaces et l'Actitité and the Compact Reconnaissance Imaging Spectrometer for Mars a…
Nightside ionosphere of Mars: Radar soundings by the Mars Express spacecraft
Gurnett, D. A.; Němec, F.; Morgan, D. D. +1 more
We present results of a survey of the nightside ionosphere of Mars as observed by Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) on board the Mars Express spacecraft. The occurrence rate of the nightside ionosphere is studied as a function of solar zenith angle (SZA), magnetic field magnitude, and magnetic field inclination. …
Spectral and stratigraphic mapping of hydrated sulfate and phyllosilicate-bearing deposits in northern Sinus Meridiani, Mars
Arvidson, R. E.; Morris, R. V.; Poulet, F. +7 more
We present detailed stratigraphic and spectral analyses that focus on a region in northern Sinus Meridiani located between 1°N to 5°N latitude and 3°W to 1°E longitude. Several stratigraphically distinct units are defined and mapped using morphologic expression, spectral properties, and superposition relationships. Previously unreported exposures …
Microscopy analysis of soils at the Phoenix landing site, Mars: Classification of soil particles and description of their optical and magnetic properties
Arvidson, R. E.; Morris, R. V.; Keller, H. U. +25 more
The optical microscope onboard the Phoenix spacecraft has returned color images (4 µm pixel-1) of soils that were delivered to and held on various substrates. A preliminary taxonomy of Phoenix soil particles, based on color, size, and shape, identifies the following particle types [generic names in brackets]: (1) reddish fines, mo…
Mountains on Titan: Modeling and observations
Showman, Adam P.; Lopes, Rosaly M. C.; Radebaugh, Jani +5 more
We have developed a thermal model of Titan's interior to study changes in volume during partial freezing or melting of a subsurface ocean due to heat flux variations from the interior. We find that the long-term cooling of Titan can cause global volume contraction ΔV/V ∼0.01. We then simulate two-dimensional contractional deformation of Titan's ic…