Search Publications
Compositional stratigraphy of clay-bearing layered deposits at Mawrth Vallis, Mars
Mustard, J. F.; Wray, J. J.; Ehlmann, B. L. +2 more
Phyllosilicates have previously been detected in layered outcrops in and around the Martian outflow channel Mawrth Vallis. CRISM spectra of these outcrops exhibit features diagnostic of kaolinite, montmorillonite, and Fe/Mg-rich smectites, along with crystalline ferric oxide minerals such as hematite. These minerals occur in distinct stratigraphic…
Anomalous Orbital-Energy Changes Observed during Spacecraft Flybys of Earth
Anderson, John D.; Campbell, James K.; Ekelund, John E. +2 more
We report and characterize anomalous orbital-energy changes observed during six Earth flybys by the Galileo, NEAR, Cassini, Rosetta, and MESSENGER spacecraft. These anomalous energy changes are consistent with an empirical prediction formula which is proportional to the total orbital energy per unit mass and which involves the incoming and outgoin…
Automatic Detection and Tracking of Coronal Mass Ejections in Coronagraph Time Series
Zhang, J.; Olmedo, O.; Poland, A. +2 more
We present the current capabilities of a software tool to automatically detect coronal mass ejections (CMEs) based on time series of coronagraph images: the solar eruptive event detection system (SEEDS). The software developed consists of several modules: preprocessing, detection, tracking, and event cataloging. The detection algorithm is based on…
Titan's middle-atmospheric temperatures and dynamics observed by the Cassini Composite Infrared Spectrometer
Nixon, Conor A.; Achterberg, Richard K.; Flasar, F. Michael +2 more
The Composite Infrared Radiometer-Spectrometer (CIRS) instrument, on the NASA Cassini Saturn orbiter, has been acquiring thermal emission spectra from the atmosphere of Titan since orbit insertion in 2004. Observation sequences for measuring stratospheric temperatures have been obtained using both a nadir mapping mode and a limb viewing mode. The …
Spectral and geological study of the sulfate-rich region of West Candor Chasma, Mars
Gendrin, Aline; Mangold, Nicolas; Bibring, Jean-Pierre +7 more
Sulfates have been discovered by the OMEGA spectrometer in different locations of the planet Mars. They are strongly correlated to light toned layered deposits in the equatorial regions. West Candor Chasma is the canyon with the thickest stack of layers and one with the largest area covered by sulfates. A detailed study coupling mineralogy derived…
Multi-wavelength observations of Galactic hard X-ray sources discovered by INTEGRAL. I. The nature of the companion star
Chaty, S.; Rahoui, F.; Foellmi, C. +3 more
Context: The INTEGRAL hard X-ray observatory has revealed an emerging population of highly obscured X-ray binary systems through multi-wavelength observations. Previous studies have shown that many of these sources are high-mass X-ray binaries hosting neutron stars orbiting around luminous and evolved companion stars.
Aims: To better understan…
Modeling Nonpotential Magnetic Fields in Solar Active Regions
van Ballegooijen, A. A.; DeLuca, E. E.; Bobra, M. G.
Electric currents are present in the coronae above solar active regions, producing nonpotential magnetic fields that can be approximated as nonlinear force-free fields (NLFFFs). In this paper NLFFF models for two active regions observed in 2002 June are presented. The models are based on magnetograms from SOHO MDI and are constrained by nonpotenti…
The type IIb SN 2008ax: the nature of the progenitor
Gal-Yam, A.; Smartt, S. J.; Maund, J. R. +9 more
A source coincident with the position of the type IIb supernova (SN) 2008ax is identified in pre-explosion Hubble Space Telescope (HST) Wide Field Planetary Camera 2 observations in three optical filters. We identify and constrain two possible progenitor systems: (i) a single massive star that lost most of its hydrogen envelope through radiatively…
Halo Gas Cross Sections and Covering Fractions of Mg II Absorption Selected Galaxies
Kacprzak, Glenn G.; Steidel, Charles C.; Churchill, Christopher W. +1 more
We examine halo gas cross sections and covering fractions, fc , of intermediate-redshift Mg II absorption selected galaxies. We computed statistical absorber halo radii, Rx, using current values of dN/dz and Schechter luminosity function parameters, and have compared these values to the distribution of impact parameters and l…
The multiwavelength variability of 3C 273
Lähteenmäki, A.; Paltani, S.; Walter, R. +11 more
Aims: We present an update of the 3C 273's database hosted by the ISDC, completed with data from radio to gamma-ray observations over the last 10 years. We use this large data set to study the multiwavelength properties of this quasar, especially focussing on its variability behaviour.
Methods: We study the amplitude of the variations and the …