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Polygonal ridge networks on Mars: Diversity of morphologies and the special case of the Eastern Medusae Fossae Formation
Head, James W.; Kerber, Laura; Dickson, James L. +1 more
Polygonal ridge networks, also known as boxwork or reticulate ridges, are found in numerous locations and geological contexts across Mars. Distinguishing the morphologies and geological context of the ridge networks sheds light on their potential as astrobiological and mineral resource sites of interest. The most widespread type of ridge morpholog…
Coogoon Valles, western Arabia Terra: Hydrological evolution of a complex Martian channel system
de Pablo, Miguel Ángel; Molina, Antonio; López, Iván +3 more
Coogoon Valles is an intricate fluvial system, and its main channel was formed during the Noachian period through the erosion of the clay-bearing basement of the Western Arabia Terra. This region is characterized by a thinner crust compared to the rest of the highlands and by the occurrence of massive phyllosilicate-bearing materials. The origin o…
Structure and density of Callisto's atmosphere from a fluid-kinetic model of its ionosphere: Comparison with Hubble Space Telescope and Galileo observations
Saur, Joachim; Strobel, Darrell F.; Hartkorn, Oliver
We develop a model of the ionospheric electron population of Jupiter's moon Callisto using a prescribed neutral atmosphere composed of O2, CO2 and H2O. A kinetic description of ionospheric suprathermal electrons coupled with a fluid description of ionospheric thermal electrons is well suited to jointly analyze and …
A possibly universal red chromophore for modeling color variations on Jupiter
Baines, K. H.; Sromovsky, L. A.; Carlson, R. W. +1 more
A new laboratory-generated chemical compound made from photodissociated ammonia (NH3) molecules reacting with acetylene (C2H2) was suggested as a possible coloring agent for Jupiter's Great Red Spot (GRS) by Carlson et al. (2016, Icarus 274, 106-115). Baines et al. (2016, Icarus, submitted) showed that the GRS spec…
HST/WFC3 observations of Uranus' 2014 storm clouds and comparison with VLT/SINFONI and IRTF/Spex observations
Wong, Michael H.; Irwin, Patrick G. J.; Orton, G. S. +2 more
In November 2014 Uranus was observed with the Wide Field Camera 3 (WFC3) instrument of the Hubble Space Telescope as part of the Hubble 2020: Outer Planet Atmospheres Legacy program, OPAL. OPAL annually maps Jupiter, Uranus and Neptune (and will also map Saturn from 2018) in several visible/near-infrared wavelength filters. The Uranus 2014 OPAL ob…
Similarity of the Jovian satellite footprints: Spots multiplicity and dynamics
Saur, J.; Badman, S. V.; Bonfond, B. +3 more
In the magnetospheres of Jupiter and Saturn, the intense interaction of the satellites Io, Europa, Ganymede and Enceladus with their surrounding plasma environment leaves a signature in the aurora of the planet. Called satellite footprints, these auroral features appear either as a single spot (Europa and Enceladus) or as multiple spots (Io and Ga…
Overview of useful spectral regions for Venus: An update to encourage observations complementary to the Akatsuki mission
Sánchez-Lavega, A.; Widemann, T.; Imamura, T. +5 more
New tables to observe the planet Venus are presented with detailed information about the main spectral regions from 100 nm to 1 mm. The information hereby is updated thanks to the Venus Express legacy and recent ground-based observations, and we hope it can constitute a helpful tool for professional and amateur observers willing to support and coo…
The Mars diffuse aurora: A model of ultraviolet and visible emissions
Gérard, J. -C.; Soret, L.; Shematovich, V. I. +2 more
A new type of Martian aurora, characterized by an extended spatial distribution, an altitude lower than the discrete aurora and electron precipitation up to 200 keV has been observed following solar activity on several occasions from the MAVEN spacecraft. We describe the results of Monte Carlo simulations of the production of several ultraviolet a…
Statistical study of Saturn's auroral electron properties with Cassini/UVIS FUV spectral images
Lamy, L.; Grodent, D.; Radioti, A. +3 more
About 2000 FUV spectra of different regions of Saturn's aurora, obtained with Cassini/UVIS from December 2007 to October 2014 have been examined. Two methods have been employed to determine the mean energy <;E> of the precipitating electrons. The first is based on the absorption of the auroral emission by hydrocarbons and the second uses the…
Cassini ISS observation of Saturn's north polar vortex and comparison to the south polar vortex
Dyudina, Ulyana A.; Ingersoll, Andrew P.; Ewald, Shawn P. +2 more
We present analyses of Saturn's north pole using high-resolution images captured in late 2012 by the Cassini spacecraft's Imaging Science Subsystem (ISS) camera. The images reveal the presence of an intense cyclonic vortex centered at the north pole. In the red and green visible continuum wavelengths, the north polar region exhibits a cyclonically…