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Origin and evolution of a cold-based tropical mountain glacier on Mars: The Pavonis Mons fan-shaped deposit
Head, James W.; Marchant, David R.; Shean, David E.
Each of the large Tharsis Montes volcanoes in the equatorial region of Mars has an unusual Amazonian-aged fan-shaped deposit on its west-northwestern flank. On the basis of Viking Orbiter data, the origin of these deposits has been variously ascribed to volcanic, mass-wasting, tectonic, and glacial processes. Using new MGS and Odyssey data, combin…
Fluid lava flows in Gusev crater, Mars
Greeley, Ronald; Williams, David A.; Neukum, Gerhard +6 more
Rocks on the floor of Gusev crater are basaltic in composition, as determined from measurements by the Mars Exploration Rover, Spirit. On the basis of compositional data, models of the basaltic lavas at the time of their emplacement suggest viscosities of 2.3 to 50 Pa . s (dependent on the number of phenocrysts and vesicles that were present), whi…
Plasma sheet turbulence observed by Cluster II
Balogh, A.; Khurana, K. K.; Kistler, L. M. +8 more
Cluster fluxgate magnetometer (FGM) and ion spectrometer (CIS) data are employed to analyze magnetic field fluctuations within the plasma sheet during passages through the magnetotail region in the summers of 2001 and 2002 and, in particular, to look for characteristics of magnetohydrodynamic (MHD) turbulence. Power spectral indices determined fro…
Observations of multiple X-line structure in the Earth's magnetotail current sheet: A Cluster case study
Balogh, A.; Dandouras, I.; Eastwood, J. P. +7 more
Observations of the Earth's magnetotail made by the four Cluster spacecraft on October 2 2003 are presented. Multi-spacecraft analysis is used to show that the variations in field and flow observed in the vicinity of the magnetotail current sheet are most consistent with a series of two active reconnection sites bounding an Earthward moving flux r…
Cassini Imaging Science: Initial Results on Saturn's Atmosphere
Burns, J. A.; Neukum, G.; Wagner, R. +32 more
The Cassini Imaging Science Subsystem (ISS) began observing Saturn in early February 2004. From analysis of cloud motions through early October 2004, we report vertical wind shear in Saturn's equatorial jet and a maximum wind speed of ~375 meters per second, a value that differs from both Hubble Space Telescope and Voyager values. We also report a…
Dynamical modelling of stars and gas in NGC 2974: determination of mass-to-light ratio, inclination and orbital structure using the Schwarzschild method
Krajnović, Davor; Emsellem, Eric; Cappellari, Michele +2 more
We study the large-scale stellar and gaseous kinematics of the E4 galaxy NGC 2974, based on panoramic integral-field data obtained with SAURON. We quantify the velocity maps with Fourier methods (kinemetry), and show that the large-scale kinematics is largely consistent with axisymmetry. We construct general axisymmetric dynamical models for the s…
On the sources of fast and slow solar wind
Schwadron, N. A.; Landi, E.; Feldman, U.
The slow speed solar wind as measured at the Earth orbit and beyond is characterized by its velocity of ≃400 km s-1, by its coronal composition and by its frozen-in temperature (from carbon charge-states) of 1.4-1.6 × 106 K. In contrast the fast speed solar wind is characterized by its velocity of ≃750 km s-1, its …
Cosmological weak lensing with the HST GEMS survey
Bell, Eric F.; Wisotzki, Lutz; Wolf, Christian +16 more
We present our cosmic shear analysis of GEMS, one of the largest wide-field surveys ever undertaken by the Hubble Space Telescope. Imaged with the Advanced Camera for Surveys (ACS), GEMS spans 795 arcmin2 in the Chandra Deep Field South. We detect weak lensing by large-scale structure in high-resolution F606W GEMS data from ~60 resolved…
Statistical Distributions of Speeds of Coronal Mass Ejections
Yurchyshyn, V.; Wang, H.; Gopalswamy, N. +2 more
We studied the distribution of plane-of-sky speeds determined for 4315 coronal mass ejections (CMEs) detected by the Large Angle and Spectrometric Coronagraph Experiment on board the Solar and Heliospheric Observatory (SOHO LASCO). We found that the speed distributions for accelerating and decelerating events are nearly identical and to a good app…
The Ice Survey Opportunity of ISO
Dartois, Emmanuel
The instruments on board the Infrared Space Observatory have for the first time allowed a complete low (PHOT, CVF) to medium resolution (SWS) spectroscopic harvest, from 2.5 to 45 µm, of interstellar dust. Amongst the detected solids present in starless molecular clouds surrounding recently born stellar and still embedded objects or products…