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Composition and Physical Properties of Enceladus' Surface
Sotin, C.; Baines, K. H.; Nicholson, P. D. +22 more
Observations of Saturn's satellite Enceladus using Cassini's Visual and Infrared Mapping Spectrometer instrument were obtained during three flybys of Enceladus in 2005. Enceladus' surface is composed mostly of nearly pure water ice except near its south pole, where there are light organics, CO2, and amorphous and crystalline water ice, …
The Latitudinal Distribution of Clouds on Titan
Montmessin, F.; Lebonnois, S.; Rannou, P. +1 more
Clouds have been observed recently on Titan, through the thick haze, using near-infrared spectroscopy and images near the south pole and in temperate regions near 40°S. Recent telescope and Cassini orbiter observations are now providing an insight into cloud climatology. To study clouds, we have developed a general circulation model of Titan that …
Giant Ringlike Radio Structures Around Galaxy Cluster Abell 3376
Paul, Surajit; Durret, Florence; Bagchi, Joydeep +1 more
In the current paradigm of cold dark matter cosmology, large-scale structures are assembling through hierarchical clustering of matter. In this process, an important role is played by megaparsec (Mpc)-scale cosmic shock waves, arising in gravity-driven supersonic flows of intergalactic matter onto dark matter-dominated collapsing structures such a…
The Interaction of the Atmosphere of Enceladus with Saturn's Plasma
Gurnett, D. A.; Lewis, G. R.; Coates, A. J. +10 more
During the 14 July 2005 encounter of Cassini with Enceladus, the Cassini Plasma Spectrometer measured strong deflections in the corotating ion flow, commencing at least 27 Enceladus radii (27 × 252.1 kilometers) from Enceladus. The Cassini Radio and Plasma Wave Science instrument inferred little plasma density increase near Enceladus. These data a…
Evidence for a Polar Ethane Cloud on Titan
Baines, K. H.; Jaumann, R.; Clark, R. +11 more
Spectra from Cassini's Visual and Infrared Mapping Spectrometer reveal the presence of a vast tropospheric cloud on Titan at latitudes 51° to 68° north and all longitudes observed (10° to 190° west). The derived characteristics indicate that this cloud is composed of ethane and forms as a result of stratospheric subsidence and the particularly coo…
A Clathrate Reservoir Hypothesis for Enceladus' South Polar Plume
Spencer, John R.; Kieffer, Susan W.; Lu, Xinli +3 more
We hypothesize that active tectonic processes in the south polar terrain of Enceladus, the 500-kilometer-diameter moon of Saturn, are creating fractures that cause degassing of a clathrate reservoir to produce the plume documented by the instruments on the Cassini spacecraft. Advection of gas and ice transports energy, supplied at depth as latent …
Explaining the Color Distributions of Globular Cluster Systems in Elliptical Galaxies
Yoon, Suk-Jin; Lee, Young-Wook; Yi, Sukyoung Ken
The colors of globular clusters in most large elliptical galaxies are bimodal. This is generally taken as evidence for the presence of two cluster subpopulations that have different geneses. However, here we find that, because of the nonlinear nature of the metallicity-to-color transformation, a coeval group of old clusters with a unimodal metalli…
A Long-Period, Violently Variable X-ray Source in a Young Supernova Remnant
Caraveo, P. A.; Bignami, G. F.; Tiengo, A. +2 more
Observations with the Newton X-ray Multimirror Mission satellite show a strong periodic modulation at 6.67 +/- 0.03 hours of the x-ray source at the center of the 2000-year-old supernova remnant RCW 103. No fast pulsations are visible. If genetically tied to the supernova remnant, the source could either be an x-ray binary, composed of a compact o…
Plasma Acceleration Above Martian Magnetic Anomalies
Coates, A. J.; Kallio, E.; Fedorov, A. +20 more
Auroras are caused by accelerated charged particles precipitating along magnetic field lines into a planetary atmosphere, the auroral brightness being roughly proportional to the precipitating particle energy flux. The Analyzer of Space Plasma and Energetic Atoms experiment on the Mars Express spacecraft has made a detailed study of acceleration p…
The Second Ring-Moon System of Uranus: Discovery and Dynamics
Showalter, Mark R.; Lissauer, Jack J.
Deep exposures of Uranus taken with the Hubble Space Telescope reveal two small moons and two faint rings. All of them orbit outside of Uranus's previously known (main) ring system but are interior to the large, classical moons. The outer new moon, U XXVI Mab, orbits at roughly twice the radius of the main rings and shares its orbit with a dust ri…