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Possible sources for methane and C2-C5 organics in the plume of Enceladus
McKay, C. P.; Khare, B. N.; Amin, R. +2 more
We consider six possible sources of CH4 and other lowmass (C2-C5) organics in the plume of Enceladus: three of these sources represent initial endowments of organics: cometary organics, Titan-like tholin, and the Fisher-Tropsch type reactions in the gases from which Enceladus formed. The other three sources represe…
The three-micron spectral feature of the Saturnian haze: Implications for the haze composition and formation process
Moses, J. I.; Courtin, R.; Kim, S. J. +3 more
We retrieve a 3.4-µm spectral feature pertaining to the Saturnian haze from Cassini/VIMS Procyon occultation data obtained at 12 different altitudes from approximately 0.7 to 0.0018 mbar (Nicholson et al., 2006; Bellucci, 2008; Bellucci et al., 2009). The occultation occurred at 55°N latitude, at the edge of the “polar hood” region, where th…
Ground-based and spacecraft observations of lightning activity on Saturn
Schneider, J.; Cecconi, B.; Fischer, G. +21 more
In late 2007, Saturn electrostatic discharges (SED) were simultaneously observed at the radio telescope UTR-2 and with the Cassini spacecraft. Observations at UTR-2 were performed with a multichannel receiver in the frequency range 12-33 MHz, and those performed on Cassini-with a swept frequency receiver that is part of the RPWS (Radio and Plasma …
Mapping Titan's surface features within the visible spectrum via Cassini VIMS
Sotin, Christophe; Barnes, Jason W.; Le Mouélic, Stéphane +10 more
Titan shows its surface through many methane windows in the 1-5 µm region. Windows at shorter wavelengths also exist, polluted by scattering off of atmospheric haze that reduces the surface contrast. At visible wavelengths, the surface of Titan has been observed by Voyager I, the Hubble Space Telescope, and ground-based telescopes. We presen…
Latitudinal variation of upper tropospheric NH3 on Saturn derived from Cassini/CIRS far-infrared measurements
Fletcher, L. N.; Irwin, P. G. J.; Calcutt, S. B. +3 more
Ammonia (NH3) has been detected both on Saturn and Jupiter, and although its concentration and distribution has been well-studied on Jupiter, it has proven more difficult to do so on Saturn due to higher sensitivity requirements resulting from Saturn's lower atmospheric temperatures and the dominance of Saturn's phosphine which masks th…
A teardrop-shaped ionosphere at Venus in tenuous solar wind
Coates, A. J.; Barabash, S.; Lundin, R. +9 more
A very tenuous solar wind regime, following a series of large coronal mass ejections, impacted Venus during early August, 2010. STEREO-B downstream from Venus observed that the solar wind density at Earth orbit dropped to ∼0.1 #/cm3 and persisted at this value over 1 day. A similar low value was observed at Earth in 1999 and has attract…
The reflectivity spectrum and opposition effect of Titan's surface observed by Huygens' DISR spectrometers
Karkoschka, Erich; Schröder, Stefan E.; Tomasko, Martin G. +1 more
We determined Titan's reflectivity spectrum near the Huygens' landing site from observations taken with the Descent Imager/Spectral Radiometer below 500 m altitude, in particular the downward-looking photometer and spectrometers. We distinguish signal coming from illumination by sunlight and the lamp onboard Huygens based on their different spectr…
Hydrocode simulations of the largest crater on asteroid Lutetia
Cremonese, G.; Marzari, F.; Preusker, F. +9 more
The flyby of the Main Belt asteroid Lutetia by the Rosetta spacecraft allows the camera OSIRIS to obtain very good images of about half of the body at the maximum resolution of 60 m per pixel. From the images and radio-science experiment, a density of about (3.4±0.3) g/cm3 has been inferred for the asteroid. Many impact craters have bee…
The OH Venus nightglow spectrum: Intensity and vibrational composition from VIRTIS—Venus Express observations
Drossart, Pierre; Piccioni, Giuseppe; Gérard, Jean-Claude +1 more
Limb spectra of the OH nightglow emission corresponding to the Δv=1 and Δv=2 sequences have been collected with the VIRTIS infrared imaging spectrograph on board Venus Express between April 2006 and October 2008. A detailed statistical analysis shows that the peak intensity and altitude of the two vibrational sequences are significantly correlated…
Study of scattering characteristics of lunar equatorial region using Chandrayaan-1 Mini-SAR polarimetric data
Saran, Sriram; Das, Anup; Mohan, Shiv +1 more
The miniaturized synthetic aperture radar Mini-SAR onboard Indian Chandrayaan-1 mission was the first ever lunar orbiting SAR that acquired several data strips covering a wide variety of geological units over lunar equatorial and low latitude regions, some of which were not studied earlier at radar wavelengths. The Mini-SAR observations, complemen…