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The origin and evolution of a differentiated Mimas

Rhoden, A. R.; Neveu, M.

In stark contrast with its neighbor moon Enceladus, Mimas is surprisingly geologically quiet, despite an eccentric orbit and distance to Saturn prone to levels of tidal dissipation 30 times higher. While Mimas' lack of geological activity could be due to a stiff, frigid interior, libration data acquired using the Cassini spacecraft suggest that it…

Spatially resolved near infrared observations of Enceladus' tiger stripe eruptions from Cassini VIMS

Nicholson, Philip D.; Hedman, Matthew M.; Clark, Roger N. +1 more

Particle properties of individual fissure eruptions within Enceladus' plume have been analyzed using high spatial resolution Visible and Infrared Mapping Spectrometer (VIMS) observations from the Cassini mission. To first order, the spectra of the materials emerging from Cairo, Baghdad and Damascus sulci are very similar, with a strong absorption …

Influence of the crustal magnetic field on the Mars aurora electron flux and UV brightness

Gérard, J. -C.; Hubert, B.; Shematovich, V. I. +1 more

Observations with the SPICAM instrument on board Mars Express have shown the occasional presence of localized ultraviolet nightside emissions associated with enhanced energetic electron fluxes. These features generally occur in regions with significant radial crustal magnetic field. We use a Monte-Carlo electron transport model to investigate the …

Analysis of R-band observations of an outburst of Comet 29P/Schwassmann-Wachmann 1 to place constraints on the nucleus' rotation state

Schambeau, Charles A.; Fernández, Yanga R.; Samarasinha, Nalin H. +2 more

We present analysis of five nights of R-band observations of Comet 29P/Schwassmann-Wachmann 1 (SW1) taken on September 2008 which show the comet undergoing an outburst. Coma morphology shows a projected asymmetric shell of material expanding radially and four linear features on the northern side of the coma at position angles 37°, 78°, 300°, and 3…

Atmospheric waves and dynamics beneath Jupiter's clouds from radio wavelength observations

de Pater, Imke; Butler, Bryan; Morales-Juberías, Raúl +3 more

We observed Jupiter at wavelengths near 2 cm with the Karl G. Jansky Very Large Array (VLA) in February 2015. These frequencies are mostly sensitive to variations in ammonia abundance and probe between ∼ 0.5 - 2.0 bars of pressure in Jupiter's atmosphere; within and below the visible cloud deck which has its base near 0.7 bars. The resultant obser…

On the link between martian total ozone and potential vorticity

Holmes, James A.; Lewis, Stephen R.; Patel, Manish R.

We demonstrate for the first time that total ozone in the martian atmosphere is highly correlated with the dynamical tracer, potential vorticity, under certain conditions. The degree of correlation is investigated using a Mars global circulation model including a photochemical model. Potential vorticity is the quantity of choice to explore the dyn…

A deep search for the release of volcanic gases on Mars using ground-based high-resolution infrared and submillimeter spectroscopy: Sensitive upper limits for OCS and SO₂

Villanueva, G. L.; Mumma, M. J.; Tokunaga, A. T. +1 more

Recent volcanic activity has long been considered a distinct possibility that would place major constraints on the evolution of Mars' interior. Volcanic activity would result in the outgassing of sulfur-bearing species. As part of our multi-band search for active release of volcanic gases on Mars, we looked for carbonyl sulfide (OCS) at its combin…

Night side distribution of SO₂ content in Venus' upper mesosphere

Montmessin, F.; Bertaux, J. -L.; Fedorova, A. A. +6 more

In this paper we present the first night side distribution of SO₂ content in Venus' upper mesosphere (altitudes from 85 to 105 km). The dataset is based on the SPICAV UV stellar occultation experiment which took place onboard ESA's Venus Express (VEX) orbiter in 2006-2014. The UV channel of SPICAV spectrometer detected absorption bands …

Diurnal variation in martian dust devil activity

Lewis, S. R.; Chapman, R. M.; Balme, M. +1 more

We show that the dust devil parameterisation in use in most Mars Global Circulation Models (MGCMs) results in an unexpectedly high level of dust devil activity during morning hours.

Prior expectations of the diurnal variation of Martian dust devils are based mainly upon the observed behaviour of terrestrial dust devils: i.e. that the majority…

Impact-generated winds on Mars

Schultz, Peter H.; Quintana, Stephanie N.

Bright and dark wind streaks across Mars record wind patterns related to atmospheric circulation. In some cases these streaks represent erosion of a surface veneer; in others, they indicate sand grains mobilized by strong vortices shed off of positive relief, such as crater rims. While many streaks change length or orientation over time, others no…