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Infrared Spectroscopy of Large, Low-Albedo Asteroids: Are Ceres and Themis Archetypes or Outliers?
Emery, Joshua P.; Rivkin, Andrew S.; Howell, Ellen S.
Low-albedo, hydrated objects dominate the list of the largest asteroids. These objects have varied spectral shapes in the 3-µm region, where diagnostic absorptions due to volatile species are found. Dawn's visit to Ceres has extended the view shaped by ground-based observing and shown that world to be a complex one, potentially still experie…
The Geology and Astrobiology of McLaughlin Crater, Mars: An Ancient Lacustrine Basin Containing Turbidites, Mudstones, and Serpentinites
Michalski, Joseph R.; Glotch, T. D.; Rogers, A. Deanne +4 more
McLaughlin crater is a 92-km diameter complex crater that formed on Mars 4 billion years ago. The resulting basin was the site of a large ( 3,000 km2), deep ( 500 m), voluminous ( 1,500 km3) Martian lake circa 3.8 Ga. While there is strong evidence that hundreds of lakes have existed on Mars at some point during the same time…
Modeled Subglacial Water Flow Routing Supports Localized Intrusive Heating as a Possible Cause of Basal Melting of Mars' South Polar Ice Cap
Butcher, F. E. G.; Balme, M. R.; Conway, S. J. +1 more
The discovery of an 20-km-wide area of bright subsurface radar reflections, interpreted as liquid water, beneath the Martian south polar layered deposits (SPLD) in data from the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) instrument, and the discovery of two geologically recent potential eskers (landforms produced by subgla…
Groundwater Control and Process Variability on the Equatorial Layered Deposits of Kotido Crater, Mars
Hauber, E.; Rossi, A. P.; Pondrelli, M. +4 more
Understanding the origin of the Hesperian-aged sulfate-bearing Equatorial Layered Deposits (ELDs) is crucial to infer Mars' climatic conditions during their formation and to assess their habitability potential. We investigated well-exposed ELDs in Kotido crater (Arabia Terra) and produced a detailed geological map of the crater infill, distinguish…
Quantitative High-Resolution Reexamination of a Hypothesized Ocean Shoreline in Cydonia Mensae on Mars
Catling, David C.; Sholes, Steven F.; Montgomery, David R.
Primary support for ancient Martian oceans has relied on qualitative interpretations of hypothesized shorelines on relatively low-resolution images and data. We present a toolkit for quantitatively identifying paleoshorelines using topographic, morphological, and spectroscopic evaluations. In particular, we apply the validated topographic expressi…
The Lomonosov Crater Impact Event: A Possible Mega-Tsunami Source on Mars
Bouley, S.; Séjourné, A.; Lagain, A. +6 more
Recent research suggests that major meteorite impact events into a Late Hesperian/Early Amazonian ocean likely produced a mega-tsunami that would have resurfaced coastal areas in northwestern Arabia Terra. The orientations of the associated lobate deposits, a conspicuous type of landforms called Thumbprint Terrain, suggests that if an impact event…
Characterizing Average Electron Densities in the Martian Dayside Upper Ionosphere
Gurnett, D. A.; Němec, F.; Morgan, D. D. +5 more
We use more than 10 years of the Martian topside ionospheric data measured by the Mars Advanced Radar for Subsurface and Ionosphere Sounding radar sounder on board the Mars Express spacecraft to derive an empirical model of electron densities from the peak altitude up to 325 km. Altogether, 16,044 electron density profiles obtained at spacecraft a…
A Thermal Inertia Map of Titan
MacKenzie, Shannon M.; Lorenz, Ralph D.; Lora, Juan M.
Like Earth, the atmosphere of Titan, Saturn's largest moon, is affected by the ability of the surface to store and release heat. Modeling efforts have shown that global temperature distributions and wind profiles differ between simulations describing Titan's surface with a uniform thermal inertia. Cassini-Huygens demonstrated, however, that a vari…
Formation of the Y Feature at the Venusian Cloud Top by Planetary-Scale Waves and the Mean Circulation: Analysis of Venus Express VMC Images
Kouyama, T.; Yamada, M.; Nara, Y. +6 more
The relationship between the planetary-scale ultraviolet contrast known as the Y feature and the wind field at the Venusian cloud top was investigated by using images obtained by Venus Monitoring Camera (VMC) on ESA's Venus Express. Spectral analyses of the ultraviolet reflectivity and the wind field revealed common periodicities of 4-5 Earth days…
The Deposition and Alteration History of the Northeast Syrtis Major Layered Sulfates
Ehlmann, B. L.; Quinn, D. P.
Ancient stratigraphy on Isidis Basin's western margin records the history of water on early Mars. Noachian units are overlain by layered, basaltic composition sedimentary rocks that are enriched in polyhydrated sulfates and capped by more resistant units. The layered sulfates—uniquely exposed at northeast Syrtis Major—comprise a sedimentary sequen…