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Comparisons of Cassini flybys of the Titan magnetospheric interaction with an MHD model: Evidence for organized behavior at high altitudes

Luhmann, J. G.; Russell, C. T.; Dougherty, M. K. +8 more

Recent papers suggest the significant variability of conditions in Saturn's magnetosphere at the orbit of Titan. Because of this variability, it was expected that models would generally have a difficult time regularly comparing to data from the Titan flybys. However, we find that in contrast to this expectation, it appears that there is underlying…

Thermal convection in the porous methane-soaked regolith in Titan: Finite amplitude convection

Czechowski, Leszek; Kossacki, Konrad J.

Titan is the only body, beside the Earth, where liquid is present on the surface. This paper is aimed to show the properties of possible convection in a porous regolith on Titan. In our previous work (Czechowski, L., Kossacki, K.J. [2009]. Icarus 202, 599-607) we showed, that the Rayleigh number Ra can exceed its critical value Ra_c. Hen…

CO prompt emission as a CO₂ marker in comets and planetary atmospheres

Slanger, Tom G.; Kalogerakis, Konstantinos S.; Ahmed, Musahid +2 more

Observations of CO emissions in the visible and near-infrared (NIR) have been rare for comets, and no measurements from orbiters are currently available in the visible for the dayglows of Mars or Venus. Analysis of the ultraviolet CO(a-X) Cameron bands from Mars Express dayglow observations supports the conclusion that these bands have very high r…

Aerial electromagnetic sounding of the lithosphere of Venus

Harrison, Keith P.; Barr, Amy C.; Grimm, Robert E. +4 more

Electromagnetic (EM) investigation depths are larger on Venus than Earth due to the dearth of water in rocks, in spite of higher temperatures. Whistlers detected by Venus Express proved that lightning is present, so the Schumann resonances ∼10-40 Hz may provide a global source of electromagnetic energy that penetrates ∼10-100 km. Electrical conduc…

Upper limits on the size of satellites of Asteroid (4) Vesta from 2007 Hubble Space Telescope observations

Mutchler, Max; Hamilton, Douglas P.; Li, Jian-Yang +4 more

We imaged the region around Asteroid (4) Vesta in nine long exposures using the Wide Field Planetary Camera 2 on the Hubble Space Telescope on May 14 and 16, 2007 to conduct a deep search for satellites in support of NASA's Dawn mission that orbited (4) Vesta in 2011-2012. Several previous search efforts have been undertaken, but no satellites wer…

Water ice abundance and CO₂ band strength on the saturnian satellite Phoebe from Cassini/VIMS observations

Hansen, Gary B.; Hollenbeck, Emily C.; Stephan, Katrin +2 more

We have studied the near-infrared spectrum of the Saturn satellite Phoebe, a distant satellite observed before Cassini's Saturn orbit insertion, using data from the Visual and Infrared Mapping Spectrometer (VIMS) on the Cassini orbiter. We have done a critical calibration of the dataset that involves careful correction of dark artifacts. We model …

HST/STIS observations and simulation of Io's emission spectrum in Jupiter shadow: Probing Io's Jupiter-facing eclipse atmosphere

Trafton, L. M.; McGrath, M. A.; Goldstein, D. B. +2 more

We report the detection of SO₂ emission from Io in Jupiter's shadow, peaking near 26 Rayleigh/Å around 3150 Å, and emission from its associated excitation-dissociation products, SO in the 2550 Å band and S I in the 1800 and 1900 Å multiplets. In addition, an unidentified emission spectrum was discovered between ∼4100 Å and ∼5700 Å, whic…

Null Variance Altitudes for the photolysis rate constants of species with barometric distribution: Illustration on Titan upper atmosphere modeling

Dobrijevic, Michel; Pernot, Pascal; Peng, Zhe +1 more

The precision of the rates of the photolysis processes initiating the complex chemistry of Titan's upper atmosphere conditions strongly the predictivity of photochemical models. Recent studies in sensitivity analysis of such models point out photolysis rate constants as key parameters. However, they have been treated approximately so far. We deal …

Microstructural penetrometry of asteroid regolith analogues and Titan's surface

Green, S. F.; Ball, A. J.; Paton, M. D.

We investigate essential aspects of penetrometer design required to measure particle properties on asteroids using a combination of laboratory analogue regoliths and spaceflight data returned by the Huygens probe from Titan. Penetrometry in granular material is complicated due to multiple and interdependent mechanical processes that occur during p…

Erratum to “Saturn’s F ring grains: Aggregates made of crystalline water ice” [Icarus 215 (2011) 682-694]

Nicholson, Philip D.; Sotin, Christophe; Clark, Roger N. +8 more