Search Publications
Disk-resolved photometry of Asteroid (2867) Steins
Jorda, L.; Lamy, P. L.; Keller, H. U. +2 more
We present a new method to perform disk-resolved photometry in order to investigate the intrinsic photometric properties of the surface of small Solar System bodies. We adopt the standard approach where a shape model is combined with a photometric formalism - in practise the Hapke formalism - to remove the effects of topography and recover the pho…
Radiative transfer analyses of Titan's tropical atmosphere
Tomasko, Martin G.; Griffith, Caitlin A.; Penteado, Paulo F. +2 more
Titan's optical and near-IR spectra result primarily from the scattering of sunlight by haze and its absorption by methane. With a column abundance of 92 km amagat (11 times that of Earth), Titan's atmosphere is optically thick and only ∼10% of the incident solar radiation reaches the surface, compared to 57% on Earth. Such a formidable atmosphere…
Geophysical evolution of Saturn's satellite Phoebe, a large planetesimal in the outer Solar System
Lunine, J. I.; Matson, D. L.; Johnson, T. V. +3 more
Saturn's satellite Phoebe is the best-characterized representative of large outer Solar System planetesimals, thanks to the close flyby by the Cassini spacecraft in June 2004. We explore the information contained in Phoebe's physical properties, density and shape, which are significantly different from those of other icy objects in its size range.…
Locations of thin liquid water layers on present-day Mars
Kereszturi, Akos; Rivera-Valentin, Edgard G.
CRISM indicates the presence of water ice patches in Richardson crater, located on Mars’ southern polar region at the area of the seasonal ice cap. Numerical simulations suggest that the maximum daytime temperature of the ice at these locations is between 195 and 220 K during local spring. Previous studies suggest that at these temperatures liquid…
Rheologies and ages of lava flows on Elysium Mons, Mars
Reiss, Dennis; Hiesinger, Harald; Pasckert, Jan Hendrik
We present results of our study of the rheologies and ages of lava flows in the Elysium Mons region of Mars. Previous studies have shown that the geometric dimensions of lava flows reflect rheological properties such as yield strength, effusion rate and viscosity. In this study the rheological properties of lava flows in the Elysium Mons region we…
Production of neutral species in Titan's ionosphere through dissociative recombination of ions
Carrasco, Nathalie; Plessis, Sylvain; Dobrijevic, Michel +1 more
The production rates of neutral species by dissociative recombination (DR) of molecular ions with electrons in the ionosphere of Titan are quantified by a new model, including, for the first time, all the available kinetic data on this process. The calculation is based on the ion densities measured by the INMS instrument on Cassini orbiter during …
Solar migrating atmospheric tides in the winds of the polar region of Venus
Hueso, R.; Sánchez-Lavega, A.; Drossart, P. +5 more
We study the effects of migrating solar tides on the winds at the cloud tops of the polar region of Venus. The winds were measured using cloud tracking on images obtained at wavelengths of 3.9 and 5.0 µm by the instrument VIRTIS-M onboard Venus Express. These wavelengths probe about the same altitude close to the cloud tops, allowing for the…
Atomic oxygen distributions in the Venus thermosphere: Comparisons between Venus Express observations and global model simulations
Gérard, J. -C.; Soret, L.; Brecht, A. S. +1 more
Nightglow emissions provide insight into the global thermospheric circulation, specifically in the transition region (∼70-120 km). The O 2 IR nightglow statistical map created from Venus Express (VEx) Visible and InfraRed Thermal Imaging Spectrometer (VIRTIS) observations has been used to deduce a three-dimensional atomic oxygen density…
Automated cloud tracking system for the Akatsuki Venus Climate Orbiter data
Imamura, Takeshi; Takagi, Masahiro; Kouyama, Toru +3 more
Japanese Venus Climate Orbiter, Akatsuki, is cruising to approach to Venus again although its first Venus orbital insertion (VOI) has been failed. At present, we focus on the next opportunity of VOI and the following scientific observations.We have constructed an automated cloud tracking system for processing data obtained by Akatsuki in the prese…
Saturn’s high degree magnetic moments: Evidence for a unique planetary dynamo
Cao, Hao; Dougherty, Michele K.; Russell, Christopher T. +2 more
Saturn’s intrinsic magnetic field has long been known to be highly axisymmetric. None of the existing field models goes beyond spherical harmonic degree 3. In this paper, we assume that the axisymmetry extends to higher degrees. This allows us to derive the degree 4 and 5 axial moments by searching their parameter space based on the Cassini Saturn…