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Widespread surface weathering on early Mars: A case for a warmer and wetter climate
Mangold, Nicolas; Bibring, Jean-Pierre; Poulet, François +2 more
Early Mars (>3 Ga) underwent aqueous alteration as evidenced by fluvial/lacustrine morphologies and the recent discovery of widespread hydrous clays. Despite compelling evidence for diverse and localized aqueous environments, the possibility for sustained liquid water globally on the martian surface and over geological timescales is still highl…
Dust aerosol, clouds, and the atmospheric optical depth record over 5 Mars years of the Mars Exploration Rover mission
Lemmon, Mark T.; Smith, Michael D.; Bell, James F., III +3 more
Dust aerosol plays a fundamental role in the behavior and evolution of the martian atmosphere. The first five Mars years of Mars Exploration Rover data provide an unprecedented record of the dust load at two sites. This record is useful for characterization of the atmosphere at the sites and as ground truth for orbital observations. Atmospheric ex…
GCM simulations of Titan's middle and lower atmosphere and comparison to observations
Lunine, Jonathan I.; Lora, Juan M.; Russell, Joellen L.
Simulation results are presented from a new general circulation model (GCM) of Titan, the Titan Atmospheric Model (TAM), which couples the Flexible Modeling System (FMS) spectral dynamical core to a suite of external/sub-grid-scale physics. These include a new non-gray radiative transfer module that takes advantage of recent data from Cassini-Huyg…
Classification and analysis of candidate impact crater-hosted closed-basin lakes on Mars
Mustard, John F.; Goudge, Timothy A.; Head, James W. +2 more
We present a new catalog of 205 candidate closed-basin lakes contained within impact craters across the surface of Mars. These basins have an inlet valley that incises the crater rim and flows into the basin but no visible outlet valley, and are considered candidate closed-basin lakes; the presence of a valley flowing into a basin does not necessi…
Seasonal variations in Titan's middle atmosphere during the northern spring derived from Cassini/CIRS observations
Bézard, Bruno; Vinatier, Sandrine; Achterberg, Richard K. +8 more
We analyzed spectra acquired at the limb of Titan in the 2006-2013 period by the Cassini/Composite Infrared Spectrometer (CIRS) in order to monitor the seasonal evolution of the thermal, gas composition and aerosol spatial distributions. We are primarily interested here in the seasonal changes after the northern spring equinox and interpret our re…
The orbits and masses of satellites of Pluto
Showalter, Mark R.; Buie, Marc W.; Jacobson, Robert A. +1 more
We present the numerically integrated orbits of Pluto's satellites. The orbits have been fit to a data set that includes Earth-based and Hubble Space Telescope (HST) astrometry of Charon, Nix, Hydra, Kerberos, and Styx, as well as the lightcurves from the Pluto-Charon mutual events. We also report new, 2010-2012 HST astrometry of all satellites in…
Mars' water vapor mapping by the SPICAM IR spectrometer: Five martian years of observations
Montmessin, Franck; Trokhimovskiy, Alexander; Bertaux, Jean-Loup +4 more
The SPICAM IR instrument on the Mars Express mission continuously observes the water vapor in the martian atmosphere starting from 2004 in the 1.38-µm spectral band. The water vapor column abundance is retrieved from nadir observations to characterize its spatial, seasonal and interannual variations. A reference set of SPICAM water vapor col…
Variability of the hydrogen in the martian upper atmosphere as simulated by a 3D atmosphere-exosphere coupling
Lopez-Valverde, M. A.; Forget, F.; Chaufray, J. -Y. +4 more
We present the temporal variability of the atomic and molecular hydrogen density derived from a 3D General Circulation Model describing the martian atmosphere from the surface to the exobase. A kinetic exospheric model is used to compute the hydrogen density above the exobase. We use these models to study the diurnal and seasonal variations of the…
VIRTIS emissivity of Alpha Regio, Venus, with implications for tessera composition
Gilmore, Martha S.; Helbert, Jörn; Mueller, Nils
The composition of Venus tessera terrain is unknown. The Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) aboard Venus Express (VEx) collects data that yields the surface emissivity at ∼1 µm, which contains information convolving a number of surface properties, including composition. We examine the variation of emissivity in the vi…
Persistent aeolian activity at Endeavour crater, Meridiani Planum, Mars; new observations from orbit and the surface
Johnson, Jeffrey R.; Chojnacki, Matthew; Moersch, Jeffrey E. +3 more
Aeolian-driven bedform activity is now known to occur in many regions of Mars, based on surface and orbital observation of contemporary martian ripple and dune mobility events. Many of these sites have only been monitored with sufficient resolution data for the last few Mars years, when the High Resolution Imaging Science Experiment (HiRISE) began…