Search Publications
Comet 67P/Churyumov-Gerasimenko: Hardening of the sub-surface layer
Kührt, E.; Spohn, T.; Kaufmann, E. +2 more
From the operation of the MUPUS thermal probe Spohn et al. (2015) concluded that the material of the nucleus of 67P/Churyumov-Gerasimenko is likely to have a high strength, at least locally at the Philae landing site. In this work we consider the derived strength of the material in order to constrain its granulation. For this purpose we performed …
Recent climate cycles on Mars: Stratigraphic relationships between multiple generations of gullies and the latitude dependent mantle
Goudge, Timothy A.; Head, James W.; Dickson, James L. +1 more
Reconstructions of the orbital parameters of Mars spanning the last ∼20 Myr, combined with global circulation models, predict multiple cycles of accumulation and degradation of an ice-rich mantle in the mid-latitudes, driven primarily by insolation at the poles during periods when obliquity was more than ten degrees greater than it is today (i.e.,…
Mars Express measurements of surface albedo changes over 2004-2010
Altieri, F.; Vincendon, M.; Audouard, J. +1 more
The pervasive Mars dust is continually transported between the surface and the atmosphere. When on the surface, dust increases the albedo of darker underlying rocks and regolith, which modifies climate energy balance and must be quantified. Remote observation of surface albedo absolute value and albedo change is however complicated by dust itself …
Deep alteration between Hellas and Isidis Basins
Quantin-Nataf, C.; Bultel, B.; Andréani, M. +2 more
Recent investigations of alteration of martian crustal outcrops suggest putative crustal hydrothermal systems, which are favorable environments for the emergence of life. In this study, we perform an analysis of the CRISM targeted observations covering crustal outcrops in the region between the Hellas and Isidis basins with the goal of investigati…
Integrating CRISM and TES hyperspectral data to characterize a halloysite-bearing deposit in Kashira crater, Mars
Mustard, John F.; Goudge, Timothy A.; Head, James W. +2 more
We present morphologic observations and spectral modeling results of a large, kaolin-group mineral-bearing deposit within Kashira crater in the southern highlands of Mars. We employ both non-linear unmixing of Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) visible to near-infrared (VNIR) reflectance data and linear unmixing of Therma…
Seasonal variation of the HDO/H2O ratio in the atmosphere of Mars at the middle of northern spring and beginning of northern summer
Aoki, Shohei; Kasaba, Yasumasa; Sagawa, Hideo +4 more
We present the seasonal variation of the HDO/H2O ratio caused by sublimation-condensation processes in a global view of the martian water cycle. The HDO/H2O ratio was retrieved from ground-based observations using high-dispersion echelle spectroscopy of the Infrared Camera and Spectrograph (IRCS) of the Subaru telescope. Coor…
Mars thermospheric scale height: CO Cameron and CO2+ dayglow observations from Mars Express
Montmessin, F.; Bertaux, J. -L.; Gérard, J. -C. +3 more
The CO Cameron (170-270 nm) and CO2+ ultraviolet doublet (298 and 299 nm) emissions have been observed on the Mars dayside with Mars Express Spectroscopy for Investigation of Characteristics of the Atmosphere of Mars (SPICAM) instrument in the limb viewing mode. These ultraviolet emissions ultimately arise from the excitation…
Constraints on the depths of origin of peak rings on the Moon from Moon Mineralogy Mapper data
Head, James W.; Baker, David M. H.
Important to understanding the process of basin formation on planetary bodies are constraints on the mineralogy and depths of origin of interior ring structures. We summarize previous analyses of the mineralogy of basin materials on the Moon and use hyperspectral image-cubes from the Chandrayaan-1's Moon Mineralogy Mapper (M3) to determ…
Variations in peak electron densities in the ionosphere of Mars over a full solar cycle
Gurnett, D. A.; Morgan, D. D.; Withers, Paul
Peak electron densities in the ionosphere of Mars are strongly influenced by the intensity of ionizing solar flux and hence by the solar cycle. Datasets used in previous studies of this relationship have incompletely sampled the range of solar irradiances encountered over a full solar cycle. Here, thousands of Mars Global Surveyor radio occultatio…
Carbon monoxide and temperature in the upper atmosphere of Venus from VIRTIS/Venus Express non-LTE limb measurements
López-Valverde, M. A.; Gilli, G.; Drossart, P. +4 more
The upper mesosphere and the lower thermosphere of Venus (from 90 to 150 km altitude) seems to play a transition region in photochemistry, dynamics and radiation, but is still very poorly constrained observationally. Since 2006 VIRTIS on board Venus Express has been obtaining limb observations of CO fluorescent infrared emissions in a systematic m…