Search Publications
Reflectance study of ice and Mars soil simulant associations-II. CO2 and H2O ice
Thomas, Nicolas; Pommerol, Antoine; Poch, Olivier +1 more
We measure the visible and near-infrared reflectance of icy analogues of the Martian surface made of CO2 ice associated in different ways with H2O ice and the regolith simulant JSC Mars-1. Such experimental results obtained with well-controlled samples in the laboratory are precious to interpret quantitatively the imaging and…
A billion or more years of possible periglacial/glacial cycling in Protonilus Mensae, Mars
Soare, R. J.; Williams, J. -P.; Hepburn, A. J. +1 more
The long-term cyclicity and temporal succession of glacial-periglacial (or deglacial) periods or epochs are keynotes of Quaternary geology on Earth. Relatively recent work has begun to explore the histories of the mid- to higher-latitudinal terrain of Mars, especially in the northern hemisphere, for evidence of similar cyclicity and succession in …
Shadow method retrievals of the atmospheric optical depth above Gale crater on Mars using HRSC images
Hoekzema, N. M.; Shaheen, Farzana; Scariah, Nayama Valsa +3 more
The 'Shadow Method' is a tool to estimate the Atmospheric Optical Depth (AOD) on Mars from the brightness of shadows. This method is derived from the equations of radiative transfer, but there are several important simplifications that together invoke errors of several tens of percent. Work by us and by others show that these errors are largely sy…
Solar occultation observations of Saturn's rings with Cassini UVIS
Colwell, J. E.; Esposito, L. W.; Becker, T. M. +2 more
The Ultraviolet Imaging Spectrograph (UVIS) instrument onboard the Cassini spacecraft observed 41 solar occultations by Saturn's rings through its extreme ultraviolet (56-118 nm) spectrographic channel. These solar occultations complement the set of stellar occultations measured by the broadband UVIS High Speed Photometer in the far ultraviolet (1…
Terrestrial Martian analogues from the Indian subcontinent: Implications for hydrological activity on Mars
Chavan, Anil; Bhandari, Subhash; Bhore, Vivek
Martian geology and surface geomorphic features are grouped under Noachian, Hesperian, and Amazonian eras, based on the crater retention ages and resurfacing ages by crater densities. Comparing the similarities and differences between Martian landforms and their terrestrial analogues promotes an understanding of how surface processes operated on b…
The current weather and climate of Mars: 12 years of atmospheric monitoring by the Planetary Fourier Spectrometer on Mars Express
Aoki, Shohei; Formisano, V.; Giuranna, Marco +5 more
We used thermal-infrared spectra returned by the Mars Express Planetary Fourier Spectrometer (PFS/MEx) to retrieve atmospheric temperature profiles, surface temperatures, and column-integrated optical depths of dust and water ice. More than 2,500,000 spectra were processed to build this new atmospheric dataset, covering the full range of season, l…
Comprehensive investigation of Mars methane and organics with ExoMars/NOMAD
Vandaele, Ann Carine; Aoki, Shohei; Liuzzi, Giuliano +17 more
Methane (CH4) on Mars has attracted a great deal of attention since it was first detected in January 2003. As methane is considered a potential marker for past/present biological or geological activity, any possible detection would require evidence with strong statistical significance. Ethane (C2H6) and ethylene (C…
Sulfuric acid vapor and sulfur dioxide in the atmosphere of Venus as observed by the Venus Express radio science experiment VeRa
Pätzold, M.; Bird, M. K.; Häusler, B. +4 more
The Venus Express radio science experiment VeRa provided more than 900 neutral atmospheric profiles between the years 2006 and 2014. About 800 of these could be used for an analysis of the radio signal absorption at X-Band (wavelength: 3.6 cm), which is mainly caused by sulfuric acid vapor within the Venus atmosphere. The absorptivity profiles wer…
Study of the hydrogen escape rate at Mars during martian years 28 and 29 from comparisons between SPICAM/Mars express observations and GCM-LMD simulations
Lopez-Valverde, M. A.; Forget, F.; Montmessin, F. +10 more
We have simulated the 3D atomic hydrogen density in the Martian upper atmosphere and associated Jeans escape rate during Martian years 28 and 29. The coronal Lyman-α brightness is computed using a 3D radiative transfer model which accounts for the monthly average hydrogen density for these two years and is compared to a large set of observations b…
Airfall on Comet 67P/Churyumov-Gerasimenko
Zacny, Kris; Bodewits, Dennis; Vincent, Jean-Baptiste +11 more
We here study the transfer process of material from one hemisphere to the other (deposition of airfall material) on an active comet nucleus, specifically 67P/Churyumov-Gerasimenko. Our goals are to: 1) quantify the thickness of the airfall debris layers and how it depends on the location of the target area, 2) determine the amount of H2…