Search Publications
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…
The lower dayside ionosphere of Mars from 14 years of MaRS radio science observations
Tellmann, Silvia; Pätzold, Martin; González-Galindo, Francisco +5 more
This work uses a subset of "quiet" MaRS ionospheric dayside observations (MaRSquiet, 2004-2017) and a 1-D photochemical model (IonA-2) to investigate the potential formation processes of the excess electron densities merged with the base of the main ionosphere (Mm). 42% of the investigated MaRS observations contain identified Mm, which …
Carbon photochemical escape rates from the modern Mars atmosphere
Yelle, Roger V.; Lillis, Robert J.; Lo, Daniel Y. +1 more
We provide a comprehensive update of photochemical escape rates of atomic carbon from the present-day Martian atmosphere using a one-dimensional photochemical model and a Monte Carlo escape model. The photochemical model incorporates new results relevant to carbon photochemistry at Mars, including new cross sections for photodissociation of CO
Sinuous ridges in Chukhung crater, Tempe Terra, Mars: Implications for fluvial, glacial, and glaciofluvial activity
Conway, Susan J.; Balme, Matthew R.; Lewis, Stephen R. +6 more
We present a geomorphic map of Chukhung crater (38.47°N, 72.42°W) in central Tempe Terra, Mars. Chukhung crater formed ~3.6-2.1 Ga, between the early Hesperian and early Amazonian periods of Mars' geologic history. It hosts dendritic networks of crater wall valleys, broad crater floor valleys, mid- to late-Amazonian-aged debris-covered glaciers, m…
Potential vorticity structure of Titan's polar vortices from Cassini CIRS observations
Nixon, Conor A.; Irwin, Patrick G. J.; Teanby, Nicholas A. +4 more
The Cassini mission has provided the best opportunity to date to extensively study the seasonal variation in Titan's atmosphere, with observations spanning almost half a Titan year (Ls = 293 - 93 °). An important feature in the Titan middle-atmosphere is the formation of a polar vortex. Observations have shown that an initially well-dev…
Morphological comparison of blocks in chaos terrains on Pluto, Europa, and Mars
Skjetne, Helle L.; Singer, Kelsi N.; Hynek, Brian M. +12 more
Chaotic terrains are characterized by disruption of preexisting surfaces into irregularly arranged mountain blocks with a "chaotic" appearance. Several models for chaos formation have been proposed, but the formation and evolution of this enigmatic terrain type has not yet been fully constrained. We provide extensive mapping of the individual bloc…