Search Publications
Modeling the plasma composition of 67P/C-G at different heliocentric distances
Ahmed, Sana; Soni, Vikas
The Rosetta spacecraft accompanied the comet 67P/C-G for nearly 2 years, collecting valuable data on the neutral and ion composition of the coma. The Rosetta Plasma Consortium (RPC) provided continuous measurements of the in situ plasma density while ROSINA-COPS monitored the neutral composition. In this work, we aim to estimate the composition of…
H2CO, O3, NH3, HCN, N2O, NO2, NO, and HO2 upper limits of detection in the Venus lower-mesosphere using SOIR on board Venus Express
Aoki, S.; Vandaele, A. C.; Trompet, L. +6 more
We report on mean upper limit number densities and volume concentrations of H2CO, O3, NH3, HCN, N2O, NO2, NO, and HO2 at the Venus terminator above the cloud layer, computed from the SOIR/Venus Express transmittances measured during hundreds of solar occultations. An unsuccessful at…
The puzzling north polar region of Uranus: Continued zero-shear winds and increasing brightness from 2015 through 2022 according to 7 years of Keck AO imaging
de Pater, Imke; Sromovsky, Lawrence A.; Fry, Patrick M. +1 more
There may be a permanent north–south asymmetry in the zonal wind profile of Uranus. According to high signal-to-noise near-IR observations with the Keck telescope NIRC2 camera, through 2014 the winds north of 60∘N had a constant (zero shear) longitudinal drift rate of 4.1∘/h westward (Sromovsky et al., 2015). Yet the south polar winds in 1986 had …
Observation of the Southern Polar cap during MY34-36 with ExoMars-TGO NOMAD LNO
Vandaele, A. C.; Daerden, F.; Thomas, I. R. +12 more
Mainly designed to study minor atmospheric species in the Martian atmosphere, the Nadir and Occultation for MArs Discovery (NOMAD) instrument suite onboard the 2016 ExoMars Trace Gas Orbiter (TGO) can also be exploited for surface ice detection. In this work, we investigate the nadir observations of the NOMAD infrared channel from the Martian Year…
Three-dimensional Venusian ionosphere model
Chaufray, Jean-Yves; Lefèvre, Franck; Lebonnois, Sébastien +3 more
To study the Venusian ionosphere, a 3D ionospheric model is included in the Venus Planetary Climate Model (Venus PCM), which we present here with a number of recent extensions and improvements. Our ionospheric model of Venus consists of 15 charged species (electron and 14 ions), 13 photo-ionization for 8 species, an ion-neutral chemistry (61 react…
Comprehensive observations and geostatistics of slope streaks within the Olympus Mons aureole
Stillman, D. E.; Primm, K. M.; Hoover, R. H. +3 more
Slope streaks (SS) are enigmatic linear features characterized by relatively low-albedo features that appear and fade on high-albedo slopes on Mars. Despite numerous hypotheses proposed to explain their formation, the primary mechanism behind SS remains elusive. Here, we examine 702 SS features using 32 multitemporal Context Imager (CTX) images an…
Martian paleolake outlet canyons - Evidence for controls on valley network formation
Sefton-Nash, Elliot; Miguel, Yamila; Diamant, Sharon J. M. +1 more
Martian valley networks (VNs) have been viewed as one of the most compelling pieces of evidence for ancient fluvial activity during the Late Noachian and Early Hesperian periods (3.7-3.5 Ga), likely as a result of precipitation (snowfall/rainfall). During this period, paleolakes also formed, predominantly due to water accumulation within impact cr…
Overview of a large observing campaign of Jupiter's aurora with the Hubble Space Telescope combined with Juno-UVS data
Bonfond, B.; Nichols, J. D.; Gérard, J. -C. +8 more
Between February and September 2019, Jupiter's ultraviolet aurorae were frequently observed during a large campaign of the Hubble Space Telescope (HST GO-15638). The campaign included approximately 10 visits around each of the perijoves of the Juno spacecraft orbits 18 to 22 around Jupiter. During this time, the solar activity was minimal, giving …
CO2 in the atmosphere of Mars depleted in 13C
Vandaele, Ann Carine; Aoki, Shohei; Liuzzi, Giuliano +14 more
We present here vertically resolved measurements of the carbon isotopic composition of CO2 in the Martian atmosphere between the surface and 50 km of altitude. The results are based on data taken by the ExoMars Trace Gas Orbiter with the NOMAD instrument and have been aggregated to derive an average vertical profile of 13C/
Crustal origin for olivine in the lunar Shioli crater ejecta boulders: Insights from the geological setting of Theophilus crater and Nectaris basin
Bhattacharya, Satadru; Pathak, Sumit; Kumar, P. Senthil +6 more
On the Moon, impact craters and basins expose a wide range of crustal and mantle rocks that provide excellent opportunity for sampling them, understanding their origins and reconstructing spatial and temporal evolution of lunar interior. The previous studies detected olivine-bearing mantle rocks in and around large impact craters and basins. The J…