Search Publications
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 …
Superpixel segmentation for analysis of hyperspectral data sets, with application to Compact Reconnaissance Imaging Spectrometer for Mars data, Moon Mineralogy Mapper data, and Ariadnes Chaos, Mars
Gilmore, Martha S.; Thompson, David R.; Anderson, Laura J. +3 more
We present a semiautomated method to extract spectral end-members from hyperspectral images. This method employs superpixels, which are spectrally homogeneous regions of spatially contiguous pixels. The superpixel segmentation is combined with an unsupervised end-member extraction algorithm. Superpixel segmentation can complement per pixel classif…
Outflow activity near Hadriaca Patera, Mars: Fluid-tectonic interaction investigated with High Resolution Stereo Camera stereo data and finite element modeling
Neukum, G.; Platz, T.; Dumke, A. +3 more
We investigate the formation of the outflow channels Dao and Niger Valles near the eastern rim of the Hellas impact basin, Mars. Methods used include image and topography analysis, surface age determination, and finite element modeling. Observations show that deep depressions, source regions for Dao and Niger Valles, are located in an area of shal…
Joule heating of the south polar terrain on Enceladus
Khurana, K. K.; Hand, K. P.; Chyba, C. F.
We report that Joule heating in Enceladus, resulting from the interaction of Enceladus with Saturn's magnetic field, may account for 150 kW to 52 MW of power through Enceladus. Electric currents passing through subsurface channels of low salinity and just a few kilometers in depth could supply a source of power to the south polar terrain, providin…
Comment on “An analysis of VLF electric field spectra measured in Titan's atmosphere by the Huygens probe” by J. A. Morente et al.
Berthelier, Jean-Jacques; Béghin, Christian; Hamelin, Michel +4 more
Abstract Available from http://www.agu.org