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Internal structure of Planum Boreum, from Mars advanced radar for subsurface and ionospheric sounding data
Plaut, J. J.; Safaeinili, A.; Aharonson, O. +1 more
An investigation of the internal structure of the ice-rich Planum Boreum (PB) deposit at the north pole of Mars is presented, using 178 orbits of Mars advanced radar for subsurface and ionospheric sounding data. For each radargram, bright, laterally extensive surface and subsurface reflectors are identified and the time delay between them is conve…
Venus' atomic hot oxygen environment
Lammer, H.; Shematovich, V. I.; Macher, W. +6 more
We present a Monte Carlo study of the atomic hot oxygen corona of Venus. In this model we consider elastic, inelastic, and quenching collisions between the traced hot particle and the ambient neutral atmosphere as well as differential cross sections to determine the scattering angle in the collisions. We also include rotational and vibrational exc…
Rift zone volcanism and associated cinder cone field in Utopia Planitia, Mars
Neukum, G.; Wagner, R.; Lanz, J. K. +2 more
We analyzed a small cone field in SW Utopia Planitia that shows striking similarities to volcanic rift zones on Earth. This is of particular interest as the study area lies off any of the volcanic centers of Mars in the northern hemisphere lowlands and is surrounded by material of the Amazonian aged Vastitas Borealis Formation (VBF). We believe th…
Spectrally distinct ejecta in Syrtis Major, Mars: Evidence for environmental change at the Hesperian-Amazonian boundary
Murchie, Scott L.; Ehlmann, Bethany L.; Mustard, John F. +2 more
Analysis of visible and near-infrared (VNIR) imaging spectrometer data of the Syrtis Major volcanic complex on Mars shows spectrally distinct ejecta (SDE) around a subset of the region's impact craters. We explore the nature of this spectral difference with the intention of constraining the physical cause of the distinction and the significance of…
Mars ultraviolet dayglow variability: SPICAM observations and comparison with airglow model
Bertaux, J. -L.; Gérard, J. -C.; Hubert, B. +2 more
Dayglow ultraviolet emissions of the CO Cameron bands and the CO2+ doublet in the Martian atmosphere have been observed with the Spectroscopy for Investigation of Characteristics of the Atmosphere of Mars on board the Mars Express spacecraft. A large amount of limb profiles has been obtained which makes it possible to analyze…
Geophysical implications of the long-wavelength topography of Rhea
Asmar, S. W.; Nimmo, F.; Thomas, P. C. +1 more
We use limb profiles to investigate the long-wavelength topography and topographic variance spectrum of Rhea. One-dimensional variance spectra show a break in slope at a wavelength of ≈300 km; a similar effect is seen on the Moon and may be a signature of an elastic lithosphere having a thickness Te ≈ 10 km. The implied heat flux is ∼15…
Magnetic and optical properties of airborne dust and settling rates of dust at the Phoenix landing site
Morris, R. V.; Drube, L.; Leer, K. +11 more
The Magnetic Properties Experiment (referred to as iSweep or Caltarget) onboard the Phoenix lander was executed in the arctic region of Mars during the mission's 152 sols lifetime. The iSweep experiment involved periodic multispectral imaging of a series of permanent ring magnets. It was designed to attract airborne magnetic dust particles to cert…
Watershed modeling in the Tyrrhena Terra region of Mars
Crown, David A.; Mest, Scott C.; Harbert, William
Watershed analyses from high-resolution image (Viking, Mars Orbiter Camera, and Thermal Emission Imaging System) and topographic (Mars Orbiter Laser Altimeter [MOLA]) data are used to qualitatively and quantitatively characterize highland fluvial systems and analyze the role of water in the evolution of Tyrrhena Terra (13°S-30°S, 265°W-280°W), Mar…
Upper limits on Titan's magnetic moment and implications for its interior
Russell, C. T.; Wei, H. Y.; Dougherty, M. K. +2 more
Measurements from the Cassini spacecraft reveal a largely magnetized ionosphere of Titan whose low-altitude fields could be from the interior of Titan or from penetrating external fields. We use the Cassini magnetic field measurements obtained during 25 Titan flybys to examine the upper limit of Titan's internal magnetic moment. The radial compone…
Lineated valley fill at the Martian dichotomy boundary: Nature and history of degradation
Neukum, G.; Hauber, E.; van Gasselt, S.
The fretted terrain of the Martian dichotomy boundary is a key region for investigating landforms related to creep of ice and debris as it exhibits landforms comparable to morphologies of periglacial environments. Although features known as lobate debris aprons, lineated valley fills and concentric crater fills have been studied in great detail, b…