Search Publications
Physics of saltation and sand transport on Titan: A brief review
Lorenz, Ralph D.
Key physical aspects of saltation and sand transport on Titan are reviewed, and the sensitivity of saltation parameters to assumptions about sand composition (most likely of 'heavy' organics) is explored. The possibility of significant triboelectric charging of sediments in Titan's low-conductivity environment is noted, and given Titan's low gravi…
Structure and dynamics of Titan’s outer icy shell constrained from Cassini data
Čadek, Ondřej; Tobie, Gabriel; Choblet, Gaël +1 more
The Cassini-Huygens mission has brought evidence for an internal ocean lying beneath an outer icy shell on Titan. The observed topography differs significantly from the reference hydrostatic shape, while the measured geoid anomalies (estimated up to degree three) remain weak. This suggests compensation either by deflections of the ocean/ice interf…
Phobos mass determination from the very close flyby of Mars Express in 2010
Pätzold, M.; Asmar, S. W.; Häusler, B. +3 more
The global geophysical parameters GMPh=(0.7072±0.0013)×10-3 km3 s-2, C20, C22 and the bulk density <ρ>=(1862±30) kg/m3 have been determined from the closest Mars Express flyby at the Mars moon Phobos on 3rd March 2010 at a distance of 77 km. The second degree gravit…
Valley formation by groundwater seepage, pressurized groundwater outbursts and crater-lake overflow in flume experiments with implications for Mars
Marra, Wouter A.; Braat, Lisanne; Baar, Anne W. +1 more
Remains of fluvial valleys on Mars reveal the former presence of water on the surface. However, the source of water and the hydrological setting is not always clear, especially in types of valleys that are rare on Earth and where we have limited knowledge of the processes involved. We investigated three hydrological scenarios for valley formation …
Open flux in Saturn’s magnetosphere
Gérard, Jean-Claude; Clarke, John T.; Badman, Sarah V. +2 more
We characterise the interaction between the solar wind and Saturn's magnetosphere by evaluating the amount of 'open' magnetic flux connected to the solar wind. This is deduced from a large set of Hubble Space Telescope images of the ultraviolet aurora, using the poleward boundary of the main aurora as a proxy for the open-closed field line boundar…
Reconstructing the aqueous history within the southwestern Melas basin, Mars: Clues from stratigraphic and morphometric analyses of fans
Williams, Rebecca M. E.; Weitz, Catherine M.
New details of the aqueous history in the southwestern Melas Chasma elevated basin have been revealed from analysis of high-resolution image, topographic and spectral datasets. We have identified eleven fan-shaped landforms that reflect various depositional environments. A distinctive marker bed with inferred indurated aeolian bedforms is within t…
How to link the relative abundances of gas species in coma of comets to their initial chemical composition?
Marboeuf, Ulysse; Schmitt, Bernard
Comets are expected to be the most primitive objects in the Solar System. The chemical composition of these objects is frequently assumed to be directly provided by the observations of the abundances of volatile molecules in the coma. The present work aims to determine the relationship between the chemical composition of the coma, the outgassing p…
New constraints on Mars rotation determined from radiometric tracking of the Opportunity Mars Exploration Rover
Park, Ryan S.; Dehant, Veronique; Kuchynka, Petr +4 more
The Opportunity Mars Exploration Rover remained stationary between January and May 2012 in order to conserve solar energy for running its survival heaters during martian winter. While stationary, extra Doppler tracking was performed in order to allow an improved estimate of the martian precession rate. In this study, we determine Mars rotation by …
Glory on Venus cloud tops and the unknown UV absorber
Roatsch, T.; Markiewicz, W. J.; Titov, D. V. +6 more
We report on the implications of the observations of the glory phenomenon made recently by Venus Express orbiter. Glory is an optical phenomenon that poses stringent constraints on the cloud properties. These observations thus enable us to constrain two properties of the particles at the cloud tops (about 70 km altitude) which are responsible for …
Physical and dynamical properties of the main belt triple Asteroid (87) Sylvia
Berthier, J.; Carry, B.; Marchis, F. +2 more
We present the analysis of high angular resolution observations of the triple Asteroid (87) Sylvia collected with three 8-10 m class telescopes (Keck, VLT, Gemini North) and the Hubble Space Telescope. The moons’ mutual orbits were derived individually using a purely Keplerian model. We computed the position of Romulus, the outer moon of the syste…