Search Publications
First extreme and far ultraviolet spectrum of a Comet Nucleus: Results from 67P/Churyumov-Gerasimenko
Stern, S. A.; Feldman, P. D.; Bertaux, J. -L. +7 more
We used the Alice spectrograph onboard the Rosetta comet orbiter spacecraft to observe the surface of Comet 67P/Churyumov-Gerasimenko in the extreme and far ultraviolet (EUV/FUV) from 700 to 2050 Å in mid-August 2014. These observations were before significant EUV/FUV coma signatures were observed by Alice. The resulting coadded spectrum has high …
A large-scale anomaly in Enceladus' microwave emission
Janssen, Michael; Ries, Paul A.
The Cassini spacecraft flew by Enceladus on 6 November 2011, configured to acquire synthetic aperture RADAR imaging of most of the surface with the RADAR instrument. The pass also recorded microwave thermal emission from most of the surface. We report on global patterns of thermal emission at 2.17 cm based on this data set in the context of additi…
Possible temperate lakes on Titan
Sotin, Christophe; Barnes, Jason W.; Le Mouélic, Stéphane +5 more
We analyze southern mid-latitude albedo-dark features on Titan observed by Cassini's Visual and Infrared Mapping Spectrometer (VIMS). In exploring the nature of these features we consider their morphology, albedo, and specular reflectivity. We suggest that they represent candidates for potential temperate lakes. The presence of lakes at the mid-la…
Candidates source regions of martian meteorites as identified by OMEGA/MEx
Bibring, J. -P.; Poulet, F.; Quantin, C. +3 more
The objective of this study is to identify and map spectral analogues of some key martian meteorites (basaltic shergottites Los Angeles, Shergotty, QUE 94201, lherzolitic shergottite ALH A77005, Nakhla, Chassigny and the orthopyroxenite ALH 84001) in order to localize terrain candidates for their source regions. We develop a best fit procedure to …
Molecular nitrogen and methane density retrievals from Cassini UVIS dayglow observations of Titan's upper atmosphere
Esposito, Larry W.; Bradley, E. Todd; Ajello, Joseph M. +4 more
We retrieve number densities of molecular nitrogen (N2) and methane (CH4) from Titan's upper atmosphere using the UV dayglow. We use Cassini Ultraviolet Imaging Spectrograph (UVIS) limb observations from 800 to 1300 km of the N I 1493 Å and N II 1085 Å multiplets, both produced directly from photofragmentation of N2
Coma dust scattering concepts applied to the Rosetta mission
Fink, Uwe; Rinaldi, Giovanna
This paper describes basic concepts, as well as providing a framework, for the interpretation of the light scattered by the dust in a cometary coma as observed by instruments on a spacecraft such as Rosetta. It is shown that the expected optical depths are small enough that single scattering can be applied. Each of the quantities that contribute t…
N2 state population in Titan's atmosphere
Galand, M.; Yelle, R. V.; Lavvas, P. +4 more
We present a detailed model for the vibrational population of all non pre-dissociating excited electronic states of N2, as well as for the ground and ionic states, in Titan's atmosphere. Our model includes the detailed energy deposition calculations presented in the past (Lavvas, P. et al. [2011]. Icarus 213(1), 233-251) as well as the …
Venus' clouds as inferred from the phase curves acquired by IR1 and IR2 on board Akatsuki
Imamura, Takeshi; Ueno, Munetaka; Kasaba, Yasumasa +12 more
We present phase curves for Venus in the 1-2 µm wavelength region, acquired with IR1 and IR2 on board Akatsuki (February-March 2011). A substantial discrepancy with the previously-published curves was found in the small phase angle range (0-30°). Through analysis by radiative-transfer computation, it was found that the visibility of larger (…
Vertical structures induced by embedded moonlets in Saturn's rings
Salo, Heikki; Spahn, Frank; Seiß, Martin +1 more
We study the vertical extent of propeller structures in Saturn's rings (i) by extending the model of Spahn and Sremčević (Spahn, F., Sremčević, M. [2000]. Astron. Astrophys., 358, 368-372) to include the vertical direction and (ii) by performing N-body box simulations of a perturbing moonlet embedded into the rings. We find that the gravitational …
To what extent can intracrater layered deposits that lack clear sedimentary textures be used to infer depositional environments?
Kah, Linda C.; Cadieux, Sarah B.
Craters within Arabia Terra, Mars, contain hundreds of meters of layered strata showing systematic alternation between slope- and cliff-forming units, suggesting either rhythmic deposition of distinct lithologies or similar lithologies that experienced differential cementation. On Earth, rhythmically deposited strata can be examined in terms of st…