Search Publications
The peculiar horizontal branch morphology of the Galactic globular clusters NGC 6388 and NGC 6441: new insights from UV observations
Djorgovski, S. G.; Zoccali, M.; Busso, G. +9 more
Context: In this paper we present multiband optical and UV Hubble Space Telescope photometry of the two Galactic globular clusters
Aims: We investigate the properties of their anomalous horizontal branches in different photometric planes in order to shed light on the nature of the ph…
A New View of the Coupling of the Sun and the Heliosphere
Zurbuchen, Thomas H.
The structure of the global heliospheric field reflects the physical properties of the low corona. The implied connections between solar and heliospheric evolution have been analyzed by a powerful multisatellite solar and heliospheric observatory that includes the Ulysses and the Solar and Heliospheric Observatory (SOHO) spacecraft. This coordinat…
Vertical profiles of HCN, HC 3N, and C 2H 2 in Titan's atmosphere derived from Cassini/CIRS data
Fletcher, L.; Irwin, P. G. J.; Teanby, N. A. +9 more
Mid-infrared limb spectra in the range 600-1400 cm-1 taken with the Composite InfraRed Spectrometer (CIRS) on-board the Cassini spacecraft were used to determine vertical profiles of HCN, HC3N, C2H2, and temperature in Titan's atmosphere. Both high (0.5 cm-1) and low (13.5 cm-1) spe…
Visual Binaries in the Orion Nebula Cluster
Bally, John; Reipurth, Bo; Connelley, Michael S. +1 more
We have carried out a major survey for visual binaries toward the Orion Nebula Cluster, using images obtained with the Advanced Camera for Surveys on the Hubble Space Telescope through an Hα filter. From 1051 stars more than 60″ from θ1 Ori C, we have selected 781 that fulfill the criteria for membership in the Orion Nebula Cluster. Amo…
Deep FORS1 Observations of the Double Main Sequence of ω Centauri
Pancino, E.; Bellazzini, M.; Origlia, L. +3 more
We present the results of a deep photometric survey performed with the VLT FORS1 aimed at investigating the complex main-sequence structure of the stellar system ω Centauri. We confirm the presence of a double main sequence and identify its blue component (bMS) over a large field of view up to 26' from the cluster center. We found that bMS stars a…
Io Volcanism Seen by New Horizons: A Major Eruption of the Tvashtar Volcano
Stern, S. A.; Weaver, H. A.; Spencer, J. R. +14 more
Jupiter’s moon Io is known to host active volcanoes. In February and March 2007, the New Horizons spacecraft obtained a global snapshot of Io’s volcanism. A 350-kilometer-high volcanic plume was seen to emanate from the Tvashtar volcano (62°N, 122°W), and its motion was observed. The plume’s morphology and dynamics support nonballistic models of l…
Saturn’s Small Inner Satellites: Clues to Their Origins
Porco, C. C.; Thomas, P. C.; Weiss, J. W. +1 more
Cassini images of Saturn’s small inner satellites (radii of less than ~100 kilometers) have yielded their sizes, shapes, and in some cases, topographies and mean densities. This information and numerical N-body simulations of accretionary growth have provided clues to their internal structures and origins. The innermost ring-region satellites have…
Pressurized oceans and the eruption of liquid water on Europa and Enceladus
Manga, M.; Wang, C. -Y.
It is difficult for liquid water to erupt onto the surface of icy satellites, such as Europa and Enceladus, because liquid water is more dense than ice. If the ice shell thickens, the volume expansion of ice upon freezing increases pressure in the subsurface ocean. The excess pressure is determined by a balance between compression of ocean water a…
Mineralogy and evolution of the surface of Mars: A review
Chevrier, V.; Mathé, P. E.
We review the mineralogy of the surface of Mars, using data from various sources, including in situ characterisations performed by landers, remote observations from orbit, and studies of the SNC meteorites. We also discuss the possible alteration processes and the factor controlling them, and try to relate the mineralogical observations to the che…
The Compact X-Ray Source 1E 1547.0-5408 and the Radio Shell G327.24-0.13: A New Proposed Association between a Candidate Magnetar and a Candidate Supernova Remnant
Gelfand, Joseph D.; Gaensler, B. M.
We present new observations of the field centered on X-ray source 1E 1547.0-5408. Analysis of a new Chandra observation shows that it is unresolved at arcsecond resolution, and analysis of a new XMM-Newton observation shows that its X-ray spectrum is best described by an absorbed power-law and blackbody model. A comparison of the X-ray flux observ…