Search Publications
Understanding the variability of nightside temperatures, NO UV and O2 IR nightglow emissions in the Venus upper atmosphere
Gérard, J. -C.; Brecht, A. S.; Bougher, S. W. +3 more
Venus Express (VEX) has been monitoring key nightglow emissions and thermal features (O2 IR nightglow, NO UV nightglow, and nightside temperatures) which contribute to a comprehensive understanding of the global dynamics and circulation patterns above ∼90 km. The nightglow emissions serve as effective tracers of Venus' middle and upper …
Interior layered deposits within a perched basin, southern Coprates Chasma, Mars: Evidence for their formation, alteration, and erosion
Hauber, E.; Le Deit, L.; Gwinner, K. +3 more
A basin-like area containing three interior layer deposits (ILDs) on the southern margin of Coprates Chasma was studied. We interpret the area as an ancestral basin and demonstrate that ILD deposition postdates the formation of the current wall rock slopes. The geometry of the ILD and the wall rock spurs form a catchment area between each ILD and …
Goldschmidt crater and the Moon's north polar region: Results from the Moon Mineralogy Mapper (M3)
Clark, R. N.; Head, J. W.; McCord, T. B. +10 more
Soils within the impact crater Goldschmidt have been identified as spectrally distinct from the local highland material. High spatial and spectral resolution data from the Moon Mineralogy Mapper (M3) on the Chandrayaan-1 orbiter are used to examine the character of Goldschmidt crater in detail. Spectral parameters applied to a north pol…
Regional-scale stratigraphy of surface units in Tyrrhena and Iapygia Terrae, Mars: Insights into highland crustal evolution and alteration history
Rogers, A. Deanne; Fergason, Robin L.
The compositional, thermophysical and geologic characteristics of surface units in Iapygia and Tyrrhena Terra (60°E-100°E, 0°-30°S) provide new insights into the compositional stratigraphy of the region. Intercrater plains are dominated by two surface units. The older unit (unit 1) is deficient in olivine and more degraded and likely consists of a…
Constraints on the origin and evolution of Iani Chaos, Mars
Muller, Jan-Peter; Warner, Nicholas H.; Gupta, Sanjeev +5 more
The origin mechanisms and geologic evolution of chaotic terrain on Mars are poorly constrained. Iani Chaos, located at the head Ares Vallis, is among the most geomorphologically complex of the chaotic terrains. Its morphology is defined by (1) multiple, 1 to 2 km deep basins, (2) flat-topped, fractured plateaus that are remnants of highland terrai…
Model calculation of N2 Vegard-Kaplan band emissions in Martian dayglow
Bhardwaj, Anil; Jain, Sonal Kumar
A model for N2 Vegard-Kaplan (VK) band (A3Σu+ - X1Σg+) emissions in Martian dayglow has been developed to explain the recent observations made by the Spectroscopy for Investigation of Characteristics of the Atmosphere of Mars (SPICAM) ultraviolet spectrograph aboard Mars …
Simulating the one-dimensional structure of Titan's upper atmosphere: 3. Mechanisms determining methane escape
Bar-Nun, Akiva; Bougher, Stephen W.; Mandt, Kathleen E. +11 more
This investigation extends the work presented by Bell et al. (2010a, 2010b). Using the one-dimensional (1-D) configuration of the Titan Global Ionosphere-Thermosphere Model (T-GITM), we quantify the relative importance of the different dynamical and chemical mechanisms that determine the CH4 escape rates calculated by T-GITM. Moreover, …
Shallow Radar (SHARAD), pedestal craters, and the lost Martian layers: Initial assessments
Head, James W.; Kadish, Seth J.; Smrekar, Suzanne E. +5 more
Since their discovery, Martian pedestal craters have been interpreted as remnants of layers that were once regionally extensive but have since been mostly removed. Pedestals span from subkilometer to hundreds of kilometers, but their thickness is less than ∼500 m. Except for a small equatorial concentration in the Medusae Fossae Formation, the nea…
The role of weathering in the formation of bedrock valleys on Earth and Mars: A numerical modeling investigation
Pelletier, Jon D.; Baker, Victor R.
Numerical models of bedrock valley development generally do not include weathering explicitly. Nevertheless, weathering is an essential process that acts in concert with the transport of loose debris by seepage and runoff to form many bedrock valleys. Here we propose a numerical model for bedrock valley development that explicitly distinguishes we…
Optical maturity variation in lunar spectra as measured by Moon Mineralogy Mapper data
Clark, R. N.; Besse, S.; Nettles, J. W. +8 more
High spectral and spatial resolution data from the Moon Mineralogy Mapper (M3) instrument on Chandrayaan-1 are used to investigate in detail changes in the optical properties of lunar materials accompanying space weathering. Three spectral parameters were developed and used to quantify spectral effects commonly thought to be associated …