Search Publications
Gasa impact crater, Mars: Very young gullies formed from impact into latitude-dependent mantle and debris-covered glacier deposits?
Head, James W.; Schon, Samuel C.
The mode of formation of gullies on Mars, very young erosional-depositional landforms consisting of an alcove, channel, and fan, is one of the most enigmatic problems in martian geomorphology. Major questions center on their ages, geographic and stratigraphic associations, relation to recent ice ages, and, if formed by flowing water, the sources o…
Atomic oxygen on the Venus nightside: Global distribution deduced from airglow mapping
Montmessin, F.; Bertaux, J. -L.; Drossart, P. +3 more
The Visible and Infra-Red Thermal Imaging Spectrometer (VIRTIS) instrument on board the Venus Express spacecraft has measured the O 2(a 1Δ) nightglow distribution at 1.27 µm in the Venus mesosphere for more than two years. Nadir observations have been used to create a statistical map of the emission on Venus nightside. …
The formation of small cones in Isidis Planitia, Mars through mobilization of pyroclastic surge deposits
Ghent, Rebecca R.; Anderson, Steven W.; Pithawala, Taronish M.
We investigate the distinctive distribution and pattern of subkilometer-sized cones in Isidis Planitia, and their relationship to the material that fills the basin. We observe that: (1) the cones show uniform size, spacing, and morphology across the entire basin; (2) they have large central depressions (relative to cone basal diameters) that are g…
Investigation of air temperature on the nightside of Venus derived from VIRTIS-H on board Venus-Express
Drossart, P.; Piccioni, G.; Lebonnois, S. +3 more
We present the spatial distribution of air temperature on Venus' night side, as observed by the high spectral resolution channel of VIRTIS (Visible and Infrared Thermal Imaging Spectrometer), or VIRTIS-H, on board the ESA mission Venus Express. The present work extends the investigation of the average thermal fields in the northern hemisphere of V…
Gullies and their relationships to the dust-ice mantle in the northwestern Argyre Basin, Mars
Hiesinger, H.; Reiss, D.; Raack, J.
We investigated gullies and their relationships to the atmospherically derived dust-ice mantle and aeolian features in the northwestern part of the Argyre basin. A detailed morphologic map of the Argyre study region allowed us to constrain the stratigraphic relationships and relative ages of gullies. In addition, we investigated the morphologic ch…
Episodic bright and dark spots on Uranus
Sromovsky, L. A.; Fry, P. M.; Hueso, R. +14 more
The northern mid-latitudes of Uranus produce greater episodes of bright cloud formation than any other region on the planet. Near 30°N, very bright cloud features were observed in 1999, 2004, and 2005, with lifetimes of the order of months. In October 2011, Gemini and HST observations revealed another unusually bright cloud feature near 23°N, whic…
Upper limits for H 2SO 4 in the mesosphere of Venus
Moriarty-Schieven, Gerald; Clancy, R. Todd; Sandor, Brad J.
Rapid temporal variability of SO 2 and SO in the Venus 85-100 km mesosphere ( Sandor, B.J., Clancy, R.T., Moriarty-Schieven G.H. [2007]. Bull. Am. Astron. Soc. 39, 503; Sandor, B.J., Clancy, R.T., Moriarty-Schieven, G.H., Mills, F.P. [2010]. Icarus 208, 49-60) requires in situ sources and sinks for these molecules. While many loss mecha…
Periglacial mass-wasting landforms on Mars suggestive of transient liquid water in the recent past: Insights from solifluction lobes on Svalbard
Hiesinger, H.; Hauber, E.; Johnsson, A. +4 more
On Earth, periglacial solifluction is a slow mass-wasting process related to freeze-thaw activity. We compare the morphology of small-scale lobate features on Mars to solifluction lobes in Svalbard to constrain their processes of formation. The analysis is based on high-resolution satellite imagery of Mars (HiRISE, ∼25 cm/pxl), aerial images of Sv…
Modeling specular reflections from hydrocarbon lakes on Titan
Nicholson, Philip D.; Sotin, Christophe; Barnes, Jason W. +9 more
During the 58th close flyby of Titan (T58), the Cassini Visual and Infrared Mapping Spectrometer (VIMS) observed a specular reflection of sunlight from Titan's Jingpo Lacus through the 5-µm methane window (Stephan, K. et al. [2010]. Geophys. Res. Lett. 37, L07104). The maximum intensity of this reflection is controlled by three basic factors…
The abundance and vertical distribution of the unknown ultraviolet absorber in the venusian atmosphere from analysis of Venus Monitoring Camera images
Esposito, Larry W.; Molaverdikhani, Karan; McGouldrick, Kevin
Observations of Venus using the ultraviolet filter of the Venus Monitoring Camera (VMC) on ESA's Venus Express Spacecraft (VEX) provide the best opportunity for study of the spatial and temporal distribution of the venusian unknown ultraviolet absorber since the Pioneer Venus (PV) mission. We compare the results of two sets of 125 radiative transf…