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Assessing the mineralogy of the watershed and fan deposits of the Jezero crater paleolake system, Mars
Mustard, John F.; Goudge, Timothy A.; Head, James W. +2 more
We present results from geomorphic mapping and visible to near-infrared spectral analyses of the Jezero crater paleolake basin and its associated watershed. The goal of this study is to understand the provenance of the sedimentary deposits within this open-basin lake using a source-to-sink approach. Two fan deposits located within the basin have d…
The Martian atmospheric ion escape rate dependence on solar wind and solar EUV conditions: 1. Seven years of Mars Express observations
Barabash, Stas; Nilsson, Hans; Holmström, Mats +3 more
More than 7 years of ion flux measurements in the energy range 10 eV-15 keV have allowed the ASPERA-3/IMA (Analyzer of Space Plasmas and Energetic Ions/Ion Mass Analyzer) instrument on Mars Express to collect a large database of ion measurements in the Mars environment, over a wide range of upstream solar wind (density and velocity) and radiation …
Variability of the Martian thermosphere during eight Martian years as simulated by a ground-to-exosphere global circulation model
Forget, F.; López-Valverde, M. A.; García-Comas, M. +3 more
Using a ground-to-exosphere general circulation model for Mars we have simulated the variability of the dayside temperatures at the exobase during eight Martian years (MY, from MY24 to MY31, approximately from 1998 to 2013), taking into account the observed day-to-day solar and dust load variability. We show that the simulated temperatures are in …
Cooling of the Martian thermosphere by CO2 radiation and gravity waves: An intercomparison study with two general circulation models
Medvedev, Alexander S.; Yiǧit, Erdal; Hartogh, Paul +3 more
Observations show that the lower thermosphere of Mars (∼100-140 km) is up to 40 K colder than the current general circulation models (GCMs) can reproduce. Possible candidates for physical processes missing in the models are larger abundances of atomic oxygen facilitating stronger CO2 radiative cooling and thermal effects of gravity wave…
Morphometry of small recent impact craters on Mars: Size and terrain dependence, short-term modification
Watters, W. A.; Geiger, L. M.; Fendrock, M. +1 more
Most recent studies of crater morphometry on Mars have addressed large craters (D>5 km) using elevation models derived from laser altimetry. In the present work, we examine a global population of small (25 m ≤D≤5 km), relatively well-preserved simple impact craters using HiRISE stereo-derived elevation models. We find that scaling laws from pri…
Identification of Mars gully activity types associated with ice composition
Vincendon, Mathieu
The detection of geologically recent channels at the end of the twentieth century rapidly suggested that liquid water could have been present on Mars up to recent times. A mechanism involving melting of water ice during ice ages in the last several million years progressively emerged during years following the first observations of these gullies. …
Electron impact ionization in the Martian atmosphere: Interplay between scattering and crustal magnetic field effects
Lillis, Robert J.; Fang, Xiaohua
Precipitating electrons are typically the dominant source of energy input into Mars' nighttime upper atmosphere, with consequences for atmospheric and ionospheric structure, composition, chemistry, and electrodynamics. Mars' spatially heterogeneous crustal magnetic fields affect the fluxes of precipitating electrons, via both the magnetic mirror f…
Compositional provinces of Mars from statistical analyses of TES, GRS, OMEGA and CRISM data
Rogers, A. Deanne; Hamilton, Victoria E.
identified 10 distinct classes of mineral assemblage on Mars through statistical analyses of mineral abundances derived from Mars Global Surveyor Thermal Emission Spectrometer (TES) data at a spatial resolution of 8 pixels per degree. Two classes are new regions in Sinus Meridiani and northern Hellas basin. Except for crystalline hematite abundanc…
Recent (Late Amazonian) enhanced backweathering rates on Mars: Paracratering evidence from gully alcoves
Conway, Susan J.; de Haas, Tjalling; Krautblatter, Michael
Mars is believed to have been exposed to low planet-wide weathering and denudation since the Noachian. However, the widespread occurrence of alcoves at the rim of pristine impact craters suggests locally enhanced recent backweathering rates. Here we derive Late Amazonian backweathering rates from the alcoves of 10 young equatorial and midlatitude …
History of the clay-rich unit at Mawrth Vallis, Mars: High-resolution mapping of a candidate landing site
Mangold, N.; Bibring, J. -P.; Poulet, F. +4 more
The Mawrth Vallis region is covered by some of the largest phyllosilicate-rich outcrops on Mars, making it a unique window into the past history of Mars in terms of water alteration, potential habitability, and the search for past life. A landing ellipse had been proposed for the Curiosity rover. This area has been extensively observed by the High…