Search Publications
High-fidelity comet 67P ephemeris and predictions based on Rosetta data
Weryk, Robert; Farnocchia, Davide; Micheli, Marco +2 more
Because of observational biases and outgassing, comets are notoriously challenging in terms of trajectory estimation and ephemeris predictions. We used tracking data collected by ESA's Rosetta mission at 67P/Churyumov-Gerasimenko to derive 10-m level constraints on the distance between the Earth and 67P in 2014 and 2016, which, together with high-…
CO2 retrievals in the Mars daylight thermosphere from its 4.3 µm limb emission measured by OMEGA/MEx
Bibring, Jean-Pierre; Gondet, Brigitte; Funke, Bernd +6 more
We present a non-local thermodynamic equilibrium retrieval scheme for atmospheric composition and its application to Mars CO2 infrared limb emissions as measured by the OMEGA instrument on board Mars Express (MEx). These emissions are caused by CO2 fluorescence of solar radiation, and thus the retrieval scheme accounts for no…
Simultaneous sublimation activity of primitive asteroids including (24) Themis and (449) Hamburga: Spectral signs of an exosphere and the solar activity impact
Petrova, Elena V.; Busarev, Vladimir V.; Irsmambetova, Tatiana R. +2 more
We describe and analyze simultaneous sublimation activity of the main-belt primitive asteroids during their perihelion passages, which was detected by spectral methods. This phenomenon was observed for the first time in September 2012 for asteroids (145) Adeona, (704) Interamnia, (779) Nina, and Mars-crosser (1474) Beira (Busarev et al., 2015, 201…
Kronoseismology V: A panoply of waves in Saturn's C ring driven by high-order internal planetary oscillations
Nicholson, Philip D.; French, Richard G.; Hedman, Matthew M. +3 more
Saturn's rings act as a system of innumerable test particles that are remarkably sensitive to periodic disturbances in the planet's gravitational field. We identify 15 additional density and bending waves in Saturn's C ring driven by the planet's internal normal mode oscillations. The collective response of the rings to Saturn's oscillations resul…
Geology and history of the Malea Planum region: A new view of Mars' oldest large volcanic province
Williams, David A.; Bernhardt, Hannes
Characterized by large paterae and late Noachian wrinkle-ridged plains, the ~1.2 million km2 Malea Planum region (MPR) has been grouped into a circum-Hellas volcanic province and likely represents the oldest of the large volcanic areas on Mars. Being key to Mars' early volcanic, tectonic, and climate evolution, we conducted a comprehens…
Modification of icy planetesimals by early thermal evolution and collisions: Constraints for formation time and initial size of comets and small KBOs
Jutzi, Martin; Golabek, Gregor J.
Comets and small Kuiper belt objects are considered to be among the most primitive objects in the solar system as comets like C/1995 O1 Hale-Bopp are rich in highly volatile ices like CO. It has been suggested that early in the solar system evolution the precursors of both groups, the so-called icy planetesimals, were modified by both short-lived …
Results from radiation environment measurements aboard ExoMars Trace Gas Orbiter in Mars science orbit in May 2018-December 2019
Semkova, Jordanka; Koleva, Rositza; Benghin, Victor +19 more
ExoMars is a joint ESA - Rosscosmos program for investigating Mars. Two missions are foreseen within this program: one consisting of the Trace Gas Orbiter (TGO), that carries scientific instruments for the detection of trace gases in the Martian atmosphere and for the location of their source regions, launched on March 14, 2016; and the other, fea…
Density structures in the martian lower thermosphere as inferred by Trace Gas Orbiter accelerometer measurements
Bruinsma, S.; Siddle, A. G.; Mueller-Wodarg, I. C. F. +1 more
ESA's Trace Gas Orbiter (TGO) undertook an aerobraking campaign to lower itself into the required science orbit. We present an overview of densities derived from TGO accelerometer data during aerobraking. With the addition of density data from NASA's MAVEN/NGIMS instrument, we infer that at TGO altitudes (105 km), the atmosphere is driven by dynam…
Io's SO2 atmosphere from HST Lyman-α images: 1997 to 2018
Giono, Gabriel; Roth, Lorenz
The atmosphere of Jupiter's volcanic moon Io consists of mainly sulfur dioxide (SO2), and this main constituent has been studied with a variety of observing techniques across many wavelengths over the years. Here we study absorption by SO2 at the hydrogen Ly-α line (1216 Å) in a large set of images taken by the Space Telescop…
Evidence for widespread glaciation in Arcadia Planitia, Mars
Osinski, Gordon R.; Golombek, Matthew P.; Williams, Nathan R. +2 more
Viscous flow features, including lobate debris aprons and lineated valley fill, are common ice-related features found across the mid-latitudes of Mars. These features are commonly found along the dichotomy boundary and around massifs where snow and ice can accumulate and flow to topographic lows during periods of higher obliquity. We have identifi…