Search Publications
Detection of Methane in the Atmosphere of Mars
Encrenaz, Thérèse; Formisano, Vittorio; Giuranna, Marco +2 more
We report a detection of methane in the martian atmosphere by the Planetary Fourier Spectrometer onboard the Mars Express spacecraft. The global average methane mixing ratio is found to be 10 +/- 5 parts per billion by volume (ppbv). However, the mixing ratio varies between 0 and 30 ppbv over the planet. The source of methane could be either bioge…
Solar Wind-Induced Atmospheric Erosion at Mars: First Results from ASPERA-3 on Mars Express
Kallio, E.; Fedorov, A.; Budnik, E. +42 more
The Analyzer of Space Plasma and Energetic Atoms (ASPERA) on board the Mars Express spacecraft found that solar wind plasma and accelerated ionospheric ions may be observed all the way down to the Mars Express pericenter of 270 kilometers above the dayside planetary surface. This is very deep in the ionosphere, implying direct exposure of the mart…
Detection of a Red Supergiant Progenitor Star of a Type II-Plateau Supernova
Smartt, Stephen J.; Mattila, Seppo; Gilmore, Gerard F. +4 more
We present the discovery of a red supergiant star that exploded as supernova 2003gd in the nearby spiral galaxy M74. The Hubble Space Telescope (HST) and the Gemini Telescope imaged this galaxy 6 to 9 months before the supernova explosion, and subsequent HST images confirm the positional coincidence of the supernova with a single resolved star tha…
Three-Dimensional Polarimetric Imaging of Coronal Mass Ejections
Davila, Joseph M.; Moran, Thomas G.
We present three-dimensional reconstructions of coronal mass ejections (CMEs), which were obtained through polarization analysis of single-view images recorded with the use of the Large Angle and Spectrometric Coronagraph (LASCO) C2 coronagraph on board the Solar and Heliospheric Observatory (SOHO) spacecraft. Analysis of a loop-like CME shows a c…
Jupiter's Atmospheric Composition from the Cassini Thermal Infrared Spectroscopy Experiment
Smith, M. D.; Strobel, D. F.; Lellouch, E. +39 more
The Composite Infrared Spectrometer observed Jupiter in the thermal infrared during the swing-by of the Cassini spacecraft. Results include the detection of two new stratospheric species, the methyl radical and diacetylene, gaseous species present in the north and south auroral infrared hot spots; determination of the variations with latitude of a…
Phase-Resolved Spectroscopy of Geminga Shows Rotating Hot Spot(s)
Caraveo, P. A.; Bignami, G. F.; Mereghetti, S. +2 more
Isolated neutron stars are seen in x-rays through their nonthermal and/or surface thermal emissions. X-ray Multimirror Mission-Newton observations of the Geminga pulsar show a 43-electron volt spectrum from the whole neutron star surface, as well as a power-law component above 2 kiloelectron volts. In addition, we have detected a hot (170 electron…