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On the orbits and masses of the satellites of the Pluto Charon system
Lee, Man Hoi; Peale, S. J.
Two small satellites of Pluto, S/2005 P1 (hereafter P1) and S/2005 P2 (hereafter P2), have recently been discovered outside the orbit of Charon, and their orbits are nearly circular and nearly coplanar with that of Charon. Because the mass ratio of Charon-Pluto is ∼0.1, the orbits of P2 and P1 are significantly non-Keplerian even if P2 and P1 have…
Ionospheric plasma acceleration at Mars: ASPERA-3 results
Coates, A. J.; Kallio, E.; Fedorov, A. +42 more
The Analyzer of Space Plasma and Energetic Atoms (ASPERA) on-board the Mars Express spacecraft (MEX) measured penetrating solar wind plasma and escaping/accelerated ionospheric plasma at very low altitudes (250 km) in the dayside subsolar region. This implies a direct exposure of the martian topside atmosphere to solar wind plasma forcing leading …
A strong vortex in Saturn's South Pole
Hueso, R.; Sánchez-Lavega, A.; Rojas, J. F. +1 more
Saturn's southern pole was observed at high resolution by the Cassini Imaging Science Subsystem (ISS) during the spacecraft insertion orbit in July 2004. Cloud tracking of individual features on images taken at a wavelength of 938 nm reveal the existence of a strong polar vortex enclosed by a jet with maximum speed of 160±10 ms relative to System …
Experimental and theoretical study of hydrocarbon photochemistry applied to Titan stratosphere
Vuitton, V.; Raulin, F.; Doussin, J. -F. +2 more
None of the Titan photochemical models currently available have been able to reproduce the full set of stratospheric molecular mixing ratios inferred from observations. In order to assess how well reaction sets describe hydrocarbon chemistry, theoretical modeling predictions were compared to the results of a laboratory experiment. A CH 4
Observations of magnetic anomaly signatures in Mars Express ASPERA-3 ELS data
Coates, A. J.; Kallio, E.; Fedorov, A. +40 more
Mars Express (MEX) Analyser of Space Plasmas and Energetic Atoms (ASPERA-3) data is providing insights into atmospheric loss on Mars via the solar wind interaction. This process is influenced by both the interplanetary magnetic field (IMF) in the solar wind and by the magnetic 'anomaly' regions of the martian crust. We analyse observations from th…
First ENA observations at Mars: Subsolar ENA jet
Coates, A. J.; Kallio, E.; Fedorov, A. +43 more
The Neutral Particle Detector (NPD), an Energetic Neutral Atom (ENA) sensor of the Analyzer of Space Plasmas and Energetic Atoms (ASPERA-3) on board Mars Express, detected intense fluxes of ENAs emitted from the subsolar region of Mars. The typical ENA fluxes are (4-7) × 10 5 cm -2 sr -1 s -1 in the ener…
Rotationally-resolved spectroscopy of Vesta I: 2 4 µm region
McFadden, L. A.; Rivkin, A. S.; Binzel, R. P. +1 more
We present new infrared (2-4 µm) spectroscopic observations of Vesta obtained in 2001, 2003, and 2004. Together with previously published work, these present a picture of how Vesta's spectrum changes with sub-Earth latitude and longitude. Vesta's albedo and 2-µm band vary regularly with its rotational phase. While establishing the cont…
Ozone abundance on Mars from infrared heterodyne spectra. I. Acquisition, retrieval, and anticorrelation with water vapor
A'Hearn, Michael F.; Sonnabend, Guido; Hewagama, Tilak +8 more
Observations of ozone on Mars were made using the Goddard Space Flight Center's Infrared Heterodyne Spectrometer and Heterodyne Instrument for Planetary Wind and Composition at the NASA Infrared Telescope Facility. Ozone is an important observable tracer of martian photochemistry. Infrared heterodyne spectroscopy with spectral resolution ⩾10 is th…
Thermal interactions of the Huygens probe with the Titan environment: Constraint on near-surface wind
Lorenz, Ralph D.
The Huygens probe lost heat to its cold environment during its descent through Titan's atmosphere and after landing. Here I report measurements of the probe's thermal behavior and comparison with ground tests (1) to provide a context for other scientific investigations, such as the release of volatiles from the landing site, and (2) to place const…
First ENA observations at Mars: Charge exchange ENAs produced in the magnetosheath
Coates, A. J.; Kallio, E.; Fedorov, A. +44 more
Measurements of energetic neutral atoms (ENA) generated in the magnetosheath at Mars are reported. These ENAs are the result of charge exchange collisions between solar wind protons and neutral oxygen and hydrogen in the exosphere of Mars. The peak of the observed ENA flux is 1.3×10 msrs. For the case studied here, i.e., the passage of Mars Expres…