Publications
Filter Total Items: 336
Storm clouds on Saturn: Lightning-induced chemistry and associated materials consistent with Cassini/VIMS spectra Storm clouds on Saturn: Lightning-induced chemistry and associated materials consistent with Cassini/VIMS spectra
Thunderstorm activity on Saturn is associated with optically detectable clouds that are atypically dark throughout the near-infrared. As observed by Cassini/VIMS, these clouds are ~20% less reflective than typical neighboring clouds throughout the spectral range from 0.8 ??m to at least 4.1 ??m. We propose that active thunderstorms originating in the 10-20 bar water-condensation region...
Authors
K. Baines, M.L. Delitsky, T.W. Momary, R. Brown, B. Buratti, R. Clark, P. Nicholson
Characterization of clouds in Titan's tropical atmosphere Characterization of clouds in Titan's tropical atmosphere
Images of Titan's clouds, possible over the past 10 years, indicate primarily discrete convective methane clouds near the south and north poles and an immense stratiform cloud, likely composed of ethane, around the north pole. Here we present spectral images from Cassini's Visual Mapping Infrared Spectrometer that reveal the increasing presence of clouds in Titan's tropical atmosphere...
Authors
C.A. Griffith, P. Penteado, S. Rodriguez, S. Le Mouelic, K. Baines, B. Buratti, R. Clark, P. Nicholson, R. Jaumann, Christophe Sotin
Saturn's Titan: Surface change, ammonia, and implications for atmospheric and tectonic activity Saturn's Titan: Surface change, ammonia, and implications for atmospheric and tectonic activity
Titan is known to have a young surface. Here we present evidence from the Cassini Visual and Infrared Mapping Spectrometer that it is currently geologically active. We report that changes in the near-infrared reflectance of a 73,000 km2 area on Titan (latitude 26° S, longitude 78° W) occurred between July 2004 and March of 2006. The reflectance of the area increased by a factor of two...
Authors
R.M. Nelson, L.W. Kamp, D. Matson, P.G.J. Irwin, K. Baines, M.D. Boryta, F.E. Leader, R. Jaumann, W. Smythe, Christophe Sotin, R. Clark, D. Cruikshank, P. Drossart, J.C. Pearl, B.W. Hapke, J. Lunine, M. Combes, G. Bellucci, J.-P. Bibring, F. Capaccioni, P. Cerroni, A. Coradini, V. Formisano, G. Filacchione, R.Y. Langevin, T. McCord, V. Mennella, P. Nicholson, B. Sicardy
Fossils, lithologies, and geophysical logs of the Mancos Shale from core hole USGS CL-1 in Montrose County, Colorado Fossils, lithologies, and geophysical logs of the Mancos Shale from core hole USGS CL-1 in Montrose County, Colorado
As part of a multidisciplinary investigation of Mancos Shale landscapes in the Gunnison Gorge National Conservation Area in Delta and Montrose Counties of western Colorado by the U.S. Geological Survey, Bureau of Land Management, and Bureau of Reclamation, a core of the Upper Cretaceous Mancos Shale was obtained from a borehole, USGS CL-1, in NE1/4 sec. 8, T. 50 N., R. 9 W....
Authors
Bridget Ball, W. Cobban, E.A. Merewether, R. I. Grauch, K.C. McKinney, K.E. Livo
VIMS spectral mapping observations of Titan during the Cassini prime mission VIMS spectral mapping observations of Titan during the Cassini prime mission
This is a data paper designed to facilitate the use of and comparisons to Cassini/visual and infrared mapping spectrometer (VIMS) spectral mapping data of Saturn's moon Titan. We present thumbnail orthographic projections of flyby mosaics from each Titan encounter during the Cassini prime mission, 2004 July 1 through 2008 June 30. For each flyby we also describe the encounter geometry...
Authors
J. Barnes, J.M. Soderblom, R. Brown, B. Buratti, Christophe Sotin, K. Baines, R. Clark, R. Jaumann, T. McCord, R. Nelson, S. Le Mouelic, S. Rodriguez, C. Griffith, P. Penteado, F. Tosi, K.M. Pitman, L. Soderblom, K. Stephan, P. Hayne, G. Vixie, J.-P. Bibring, G. Bellucci, F. Capaccioni, P. Cerroni, A. Coradini, D. Cruikshank, P. Drossart, V. Formisano, Y. Langevin, D. Matson, P. Nicholson, B. Sicardy
Global circulation as the main source of cloud activity on Titan Global circulation as the main source of cloud activity on Titan
Clouds on Titan result from the condensation of methane and ethane and, as on other planets, are primarily structured by circulation of the atmosphere. At present, cloud activity mainly occurs in the southern (summer) hemisphere, arising near the pole and at mid-latitudes from cumulus updrafts triggered by surface heating and/or local methane sources, and at the north (winter) pole...
Authors
S. Rodriguez, S. Le Mouelic, P. Rannou, G. Tobie, K. Baines, J. Barnes, C.A. Griffith, M. Hirtzig, K.M. Pitman, Christophe Sotin, R. Brown, B. Buratti, R. Clark, P. Nicholson
The geology of Hotei Regio, Titan: Correlation of Cassini VIMS and RADAR The geology of Hotei Regio, Titan: Correlation of Cassini VIMS and RADAR
Joint Cassini VIMS and RADAR SAR data of ∼700-km-wide Hotei Regio reveal a rich collection of geological features that correlate between the two sets of images. The degree of correlation is greater than anywhere else seen on Titan. Central to Hotei Regio is a basin filled with cryovolcanic flows that are anomalously bright in VIMS data (in particular at 5 μm) and quite variable in...
Authors
L.A. Soderblom, R. Brown, J.M. Soderblom, J. Barnes, R. Kirk, Christophe Sotin, R. Jaumann, D. MacKinnon, D.W. Mackowski, K. Baines, B. Buratti, R. Clark, P. Nicholson
Detection of adsorbed water and hydroxyl on the moon Detection of adsorbed water and hydroxyl on the moon
Data from the Visual and Infrared Mapping Spectrometer (VIAAS) on Cassini during its flyby of the AAoon in 1999 show a broad absorption at 3 micrometers due to adsorbed water and near 2.8 micrometers attributed to hydroxyl in the sunlit surface on the AAoon. The amounts of water indicated in the spectra depend on the type of mixing and the grain sizes in the rocks and soils but could be...
Authors
R. Clark
Photometric changes on Saturn's Titan: Evidence for active cryovolcanism Photometric changes on Saturn's Titan: Evidence for active cryovolcanism
We report infrared spectrophotometric variability on the surface of Saturn's moon Titan detected in images returned by the Visual and Infrared Mapping Spectrometer (VIMS) onboard the Cassini Saturn Orbiter. The changes were observed at 7°S, 138°W and occurred between October 27, 2005 and January 15, 2006. After that date the surface was unchanged until the most recent observation, March...
Authors
Robert Nelson, Lucas Kamp, Rosaly Lopes, Dennis Matson, Randolph Kirk, Bruce Hapke, Stephen Wall, Mark Boryta, Frank Leader, William Smythe, Karl Mitchell, Kevin Baines, Ralf Jaumann, Christophe Sotin, Roger Clark, Dale Cruikshank, Pierre Drossart, Jonathan Lunine, Michel Combes, Giancarlo Bellucci, Jean-Pierre Bibring, Fabrizio Capaccioni, Pricilla Cerroni, Angioletta Coradini, Vittorio Formisano, Gianrico Filacchione, Yves Langevin, Thomas McCord, Vito Mennella, Philip Nicholson, Bruno Sicardy, Patrick Irwin, John Pearl
Reflectance spectroscopy of organic compounds: 1. Alkanes Reflectance spectroscopy of organic compounds: 1. Alkanes
Reflectance spectra of the organic compounds comprising the alkane series are presented from the ultraviolet to midinfrared, 0.35 to 15.5 /??m. Alkanes are hydrocarbon molecules containing only single carbon-carbon bonds, and are found naturally on the Earth and in the atmospheres of the giant planets and Saturn's moon, Titan. This paper presents the spectral properties of the alkanes as...
Authors
R. Clark, J. Curchin, T.M. Hoefen, G.A. Swayze
Identification of hydrated silicate minerals on Mars using MRO-CRISM: Geologic context near Nili Fossae and implications for aqueous alteration Identification of hydrated silicate minerals on Mars using MRO-CRISM: Geologic context near Nili Fossae and implications for aqueous alteration
[1] The Noachian terrain west of the Isidis basin hosts a diverse collection of alteration minerals in rocks comprising varied geomorphic units within a 100,000 km2 region in and near the Nili Fossae. Prior investigations in this region by the Observatoire pour l'Minéralogie, l'Eau, les Glaces, et l'Activité (OMEGA) instrument on Mars Express revealed large exposures of both mafic...
Authors
B.L. Ehlmann, J.F. Mustard, G.A. Swayze, R. Clark, J.L. Bishop, F. Poulet, D.J. Des Marais, L.H. Roach, R.E. Milliken, J.J. Wray, O. Barnouin-Jha, S.L. Murchie
Characterization of phyllosilicates observed in the central Mawrth Vallis region, Mars, their potential formational processes, and implications for past climate Characterization of phyllosilicates observed in the central Mawrth Vallis region, Mars, their potential formational processes, and implications for past climate
Mawrth Vallis contains one of the largest exposures of phyllosilicates on Mars. Nontronite, montmorillonite, kaolinite, and hydrated silica have been identified throughout the region using data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM). In addition, saponite has been identified in one observation within a crater. These individual minerals are identified and
Authors
N.K. McKeown, J.L. Bishop, E.Z. Noe Dobrea, B.L. Ehlmann, M. Parente, J.F. Mustard, S.L. Murchie, G.A. Swayze, J.-P. Bibring, E. Silver