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The Mars Express Observatoire pour la Minéralogie, l'Eau, les Glaces et l'Activité (OMEGA) collected an unprecedented visible and near-infrared hyperspectral dataset covering the low albedo regions of Mars. We investigate the ability to infer modal abundance of surfaces of these regions from a radiative transfer model developed by Shkuratov et al. [Shkuratov, Y., Starukhina, L., Hoffmann, H., Arnold,...
The rotation of Mercury is presently captured in a 3/2 spin–orbit resonance with the orbital mean motion. The capture mechanism is well understood as the result of tidal interactions with the Sun combined with planetary perturbations [Goldreich, P., Peale, S., 1966. Astron. J. 71, 425–438; Correia, A.C.M., Laskar, J., 2004. Nature 429, 848–850]. However, it is now almost certain that Mercury has a...
Sporadic meteoroids are the most abundant yet least understood component of the Earth's meteoroid complex. This paper aims to build a physics-based model of this complex calibrated with five years of radar observations. The model of the sporadic meteoroid complex presented here includes the effects of the Sun and all eight planets, radiation forces and collisions. The model uses the observed meteor...
Since 2004, observations of Saturn's F-ring have revealed that the ring's core is surrounded by structures with radial scales of hundreds of kilometers, called “spirals” and “jets.” Gravitational scattering by nearby moons was suggested as a potential production mechanism; however, it remained doubtful because a population of Prometheus-mass moons is needed and, obviously, such a population does not...
Near–Earth Asteroid 4660 Nereus has been identified as a potential spacecraft target since its 1982 discovery because of the low delta-V required for a spacecraft rendezvous. However, surprisingly little is known about its physical characteristics. Here we report Arecibo (S-band, 2380-MHz, 13-cm) and Goldstone (X-band, 8560-MHz, 3.5-cm) radar observations of Nereus during its 2002 close approach....
We examine the hypothesis that within close binary asteroid systems with super-synchronously rotating, roughly spheroidal primary (Alpha) and synchronous elongated secondary (Beta), continued YORP angular acceleration of the primary causes it to spin at rates where loose material near its equator is lofted from the surface. Subsequent interaction of the material with the binary components causes that...
We present in this work the observations performed with SINFONI in the framework of a new ESO-Large Program (2006–2008) on Trans-Neptunian Objects (TNOs) and Centaurs. We obtained 21 near-infrared (1.49 to 2.4 microns) spectra of high quality, including 4 spectra of objects never observed before. We search for the presence of features due to ices, particularly water ice. Eris is the only object showing...
Europa is bombarded by intense radiation that erodes the surface, launching molecules into a thin “atmosphere” representative of surface composition. In addition to atoms and molecules created in the mostly water ice surface such as H 2 O, O 2 , H 2 , the atmosphere is known to have species representative of trace surface materials. These trace species are carried off with...
The results of V-band polarimetric observations of the potentially hazardous near-Earth Asteroid (23187) 2000 PN 9 at large phase angles are presented as well as its photometric observations in BVRI bands. Observations were made in March–April 2006 during its close approach to the Earth using the 1.82-m Asiago telescope (Italy) and the 0.7-m telescope at the Chuguevskaya Observational Station...
Curve fitting techniques are a widespread approach to spectral modeling in the VNIR range [Burns, R.G., 1970. Am. Mineral. 55, 1608–1632; Singer, R.B., 1981. J. Geophys. Res. 86, 7967–7982; Roush, T.L., Singer, R.B., 1986. J. Geophys. Res. 91, 10301–10308; Sunshine, J.M., Pieters, C.M., Pratt, S.F., 1990. J. Geophys. Res. 95, 6955–6966]. They have been successfully used to model reflectance spectra...
A fast method is presented for deriving the tropospheric CO concentrations in the Venus atmosphere from near-infrared spectra using the night side 2.3 μm window. This is validated using the spectral fitting techniques of Tsang et al. [Tsang, C.C.C., Irwin, P.G.J., Taylor, F.W., Wilson, C.F., Drossart, P., Piccioni, G., de Kok, R., Lee, C., Calcutt, S.B., and the Venus Express/VIRTIS Team, 2008a. Tropospheric...
An extensive set of HI Lyman-α images obtained with the Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph (STIS) from 1997–2001 has been analyzed to provide information about the spatial and temporal character of Io's SO 2 atmosphere. An atmospheric distribution map derived from the observations reveals that the sunlit SO 2 atmosphere is temporally stable on a global...
We have measured the vertical shear of the zonal winds in the cloud-haze upper layer of Saturn using Cassini ISS images obtained in the filters MT2 (753 nm methane absorption band, sensitive to the upper haze) and CB2 (adjacent continuum, sensitive to the lower cloud). Our radiative transfer models indicate that at the eastward jet peaks these filters are sensing clouds at the respective ∼100 mbar...
We present observations of a local dust storm performed by the OMEGA and PFS instruments aboard Mars Express. OMEGA observations are used to retrieve the dust single-scattering albedo in the spectral range 0.4–4.0 μm. The single-scattering albedo shows fairly constant values between 0.6 and 2.6 μm, and a sharp decrease at wavelengths shorter than 0.6 μm, in agreement with previous studies. It presents...
In this paper we investigate the formation of the Cretaceous–Paleogene (K–Pg) boundary layer through numerical modeling. The K–Pg layer is widely agreed to be composed of meteoritic material and target rock from the Chicxulub impact site, that has been ejected around the globe and mixed with local material during final deposition. The observed composition and thickness of the K–Pg boundary layer changes...
The south residual cap of Mars is commonly described as a thin and bright layer of CO 2 -ice. The Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) is a low-frequency radar on board Mars Express operating at the wavelength between 55 and 230 m in vacuum. The reflection of the radar wave on a stratified medium like the residual cap can generate interferences, causing weaker...
Since our technological civilisation depends on our planet's properties, anthropic selection can explain the close match between the high 26 Al/ 27 Al ratios in the earliest Solar System solids, which are difficult to produce in models of star-formation, and the limiting value required to cause (the widely observed) thermal processing of planetesimals. We suggest that volatile loss...
The IRAM Plateau de Bure Interferometer has been used to map the CO(1–0) rotational line in Mars' middle atmosphere. Absolute winds and thermal profiles were retrieved during the 1999, 2001, 2003 and 2005 planet's oppositions. The observations sampled various seasons (Ls=143, 196, 262, 317 and 322), and different dust situations (clear, global storm, regional storm). The absolute winds were derived...
A fully 3-dimensional implicit numerical model for comet nucleus evolution is presented, emphasizing dust mantle formation. A spherical configuration is considered with an initial composition of amorphous H 2 O ice and dust, taking into account a discrete dust-grain size distribution. The model is applied to Comet 67P/Churyumov–Gerasimenko, adopting its orbital elements, rotation period and...
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