Search Publications
Common origin of trapped volatiles in oxidized icy moons and comets
Johnson, Robert E.; Oza, Apurva V.
Following spacecraft encounters with comets 67P/C-G and 1P/Halley, it was surprising that O2, expected to be a very minor species in their comas, was observed to outgas at a few percent abundance during their ice sublimation phases. This challenged the direct connection suggested between comets and material in the interstellar medium (I…
Unambiguous detection of mesospheric CO2 clouds on Mars using 2.7 µm absorption band from the ACS/TGO solar occultations
Grigoriev, A.; Montmessin, F.; Fedorova, A. +5 more
Mesospheric CO2 clouds are one of two types of carbon dioxide clouds known on Mars. We present observations of mesospheric CO2 clouds made by Atmospheric Chemistry Suite (ACS) onboard the ESA-Roscosmos ExoMars Trace Gas Orbiter (TGO). We analyzed 1663 solar occultation sessions of Thermal InfraRed (TIRVIM) and Middle InfraRed…
A Mars orbital catalog of aqueous alteration signatures (MOCAAS)
Bibring, Jean-Pierre; Langevin, Yves; Gondet, Brigitte +3 more
We describe the completion of the MOCAAS project providing a global repository of secondary minerals formed through interaction with water on Mars. This work is based on the analysis of orbital imaging spectroscopy data from the OMEGA/Mars Express and CRISM/MRO near-infrared instruments. A database and a set of high-resolution global maps (200 m/p…
Three-dimensional modeling of Venus photochemistry and clouds
Stolzenbach, Aurélien; Lefèvre, Franck; Määttänen, Anni +1 more
We present here three-dimensional simulations of the Venus photochemistry and clouds from the ground to the bottom of the thermosphere. For that purpose, we have implemented a state-of-the-art photochemical and equilibrium cloud model in the Venus Planetary Climate Model (Venus PCM). The interactive coupling between dynamics, radiation, chemistry …
Solar cycle variation of ion escape from Mars
Barabash, Stas; Nilsson, Hans; Zhang, Qi +6 more
Using Mars Express data from 2007 until 2020 we show how ion outflow from Mars varied over more than a solar cycle, from one solar minimum to another. The data was divided into intervals with a length of one Martian year, starting from 30 April 2007 and ending 13 July 2020. The net escape rate was about 5 × 1024s-1 in the fir…
Exploring the variability of the venusian thermosphere with the IPSL Venus GCM
Lefèvre, Franck; Lebonnois, Sébastien; Millour, Ehouarn +4 more
Recent simulations of the Institut Pierre-Simon Laplace (IPSL) Venus Global Climate Model (VGCM) developed at the Laboratoire de Météorologie Dynamique (LMD) were performed with a model top raised from ∼10-5 (∼150 km) to ∼10-8 Pa (180-250 km; upper boundary). The parameterizations of non-LTE CO2 near infrared heati…
Update on SO2, detection of OCS, CS, CS2, and SO3, and upper limits of H2S and HOCl in the Venus mesosphere using SOIR on board Venus Express
Aoki, S.; Vandaele, A. C.; Trompet, L. +6 more
We report on the update of SO2 and first detections of SO3, CS, and CS2, and detection of OCS above the cloud deck using the SOIR instrument on-board Venus Express, and upper limit profiles of H2S and HOCl. Based on the solar occultation spectra measured by SOIR covering all latitudes over the 2006-2014 …
Saturn's atmospheric response to the large influx of ring material inferred from Cassini INMS measurements
Fletcher, Leigh N.; Guerlet, Sandrine; Moses, Julianne I. +12 more
During the Grand Finale stage of the Cassini mission, organic-rich ring material was discovered to be flowing into Saturn's equatorial upper atmosphere at a surprisingly large rate. Through a series of photochemical models, we have examined the consequences of this ring material on the chemistry of Saturn's neutral and ionized atmosphere. We find …
Ganymede's atmosphere as constrained by HST/STIS observations
Leblanc, F.; Galand, M.; Roth, L. +7 more
A new analysis of aurora observations of Ganymede's atmosphere on the orbital leading and trailing hemispheres has been recently published by Roth et al. (2021), suggesting that water is its main constituent near noon. Here, we present two additional aurora observations of Ganymede's sub-Jovian and anti-Jovian hemispheres, which suggest a modulati…
Evolution of Neptune at near-infrared wavelengths from 1994 through 2022
de Pater, Imke; Wong, Michael H.; Hueso, Ricardo +16 more
Using archival near-infrared observations from the Keck and Lick Observatories and the Hubble Space Telescope, we document the evolution of Neptune's cloud activity from 1994 to 2022. We calculate the fraction of Neptune's disk that contained clouds, as well as the average brightness of both cloud features and cloud-free background over the planet…