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Titan's surface before Cassini
Lorenz, Ralph D.; Lunine, Jonathan I.
We review current understanding of Titan's surface, synthesizing a paradigm from Earth-based radar observations and near-infrared surface maps, together with reanalysis of Voyager data and results from published theoretical models. Based on these we suggest that Titan has a varied landscape with a variety of tectonic and erosive features indicativ…
Discovery of 1323 s pulsations from RX J0103.6-7201: The longest period X-ray pulsar in the SMC
Pietsch, W.; Haberl, F.
XMM-Newton archival observations of the Be/X-ray binary candidate revealed pulsations with a period of ~1323 s. This makes the X-ray pulsar with the longest period known in the Small Magellanic Cloud (SMC). More than 150 X-ray observations of by ROSAT, Chandra and XMM-Newton show flux variations by a factor of 50 on time scales of days to years. U…
Convective plumes and the scarcity of Titan's clouds
Lorenz, Ralph D.; McKay, Christopher P.; Griffith, Caitlin A. +2 more
We show that simple thermodynamic models of convective plumes predict the area fraction of convective plumes (i.e., updrafts) in Titan's atmosphere to be ~12 smaller than on Earth. This result is in agreement with predictions by sophisticated dynamical models and with the relative tropospheric cloud cover, which is only ~1% on Titan. Rainstorms on…
Thermal evolution model of 67P/Churyumov-Gerasimenko, the new Rosetta target
Coradini, A.; Capria, M. T.; de Sanctis, M. C.
Rosetta, the ESA mission dedicated to the detailed study of a comet nucleus before and after the onset of activity, will arrive at comet 67P/Churyumov-Gerasimenko in 2014. At the moment, little is known about this comet, but the successful design of the ROSETTA mission requires some preliminary knowledge of the comet physical parameters. These qua…
Spectrophotometry of the small satellites of Saturn and their relationship to Iapetus, Phoebe, and Hyperion
Buratti, B. J.; Hicks, M. D.; Davies, A.
We have obtained broadband spectrophotometric observations of four of the recently discovered small satellites of Saturn (Gladman et al., 2001, Nature 412, 163-166). The new data enable an understanding of the provenance, composition, and interrelationships among these satellites and the other satellites of Saturn, particularly Iapetus, Phoebe, an…
Hubble Space Telescope NICMOS Imaging Polarimetry of Proto-Planetary Nebulae: Probing the Dust Shell Structure via Polarized Light
Ueta, Toshiya; Meixner, Margaret; Murakawa, Koji
Using NICMOS on the Hubble Space Telescope, we have performed imaging polarimetry of proto-planetary nebulae (PPNs). Our objective is to study the structure of optically thin circumstellar shells of post-asymptotic giant branch (AGB) stars by separating dust-scattered, linearly polarized starlight from unpolarized direct starlight. This unique tec…
The Nonhomologous Nature of Solar Diameter Variations
Basu, Sarbani; Sofia, Sabatino; Demarque, Pierre +2 more
We show in this Letter that the changes of the solar diameter in response to variations of large-scale magnetic fields and turbulence are not homologous. For the best current model, the variation at the photospheric level is over 1000 times larger than the variation at a depth of 5 Mm, which is about the level at which f-mode solar oscillations de…
Velocity field and star formation in the Horsehead nebula
Teyssier, D.; Güsten, R.; Hily-Blant, P. +1 more
Using large scale maps in C18O(2-1) and in the continuum at 1.2 mm obtained at the IRAM-30 m antenna with the Heterodyne Receiver Array (HERA) and MAMBO2, we investigated the morphology and the velocity field probed in the inner layers of the Horsehead nebula. The data reveal a non-self-gravitating (m/m_vir≈ 0.3) filament of dust and ga…
Absolute Proper Motion of the Canis Major Dwarf Galaxy Candidate
Rix, Hans-Walter; Peñarrubia, Jorge; Girard, Terrence M. +4 more
We have measured the absolute proper motion of the candidate Canis Major dwarf galaxy (CMa), at (l,b)=(240°,-8°). Likely main-sequence stars in CMa have been selected from a region in the color-magnitude diagram that has very little contamination from known Milky Way components. We obtain µlcosb=-1.47+/-0.37 and µb
Preliminary results on Saturn's inner plasmasphere as observed by Cassini: Comparison with Voyager
Coates, A. J.; Crary, F.; Johnson, R. E. +12 more
We present an analysis of Saturn's inner plasmasphere as observed by the Cassini Plasma Spectrometer (CAPS) experiment during Cassini's initial entry into Saturn's magnetosphere when the spacecraft was inserted into orbit around Saturn. The ion fluxes are divided into two sub-groups: protons and water group ions. We present the relative amounts of…