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Astrobiology and habitability of Titan
Raulin, Francois
Largest satellite of Saturn and the only in the solar system having a dense atmosphere, Titan is one of the key planetary bodies for astrobiological studies, due to several aspects. (i) Its analogies with planet Earth, in spite of much lower temperatures, with, in particular, a methane cycle on Titan analogous to the water cycle on Earth. (ii) The…
Accurate Mars Express orbits to improve the determination of the mass and ephemeris of the Martian moons
Pätzold, M.; Rosenblatt, P.; Le Maistre, S. +5 more
The determination of the ephemeris of the Martian moons has benefited from observations of their plane-of-sky positions derived from images taken by cameras onboard spacecraft orbiting Mars. Images obtained by the Super Resolution Camera (SRC) onboard Mars Express (MEX) have been used to derive moon positions relative to Mars on the basis of a fit…
The dust trail of Comet 67P/Churyumov Gerasimenko
Reach, William T.; Kelley, Michael S.; Lien, David J.
We report the detection of Comet 67P/Churyumov-Gerasimenko's dust trail and nucleus in 24 µm Spitzer Space Telescope images taken February 2004. The dust trail is not found in optical Palomar images taken June 2003. Both the optical and infrared images show a distinct neck-line tail structure, offset from the projected orbit of the comet. We…
Detection of C 2HD and the D/H ratio on Titan
Vinatier, Sandrine; Nixon, Conor A.; Jolly, Antoine +8 more
We report here the first detection of mono-deuterated acetylene (acetylene-d1, C 2HD) in Titan's atmosphere from the presence of two of its emission bands at 678 and 519 cm -1 as observed in CIRS spectral averages of nadir and limb observations taken between July 2004 and mid-2007. By using new laboratory spectra for this mol…
Triaxial ellipsoid dimensions and rotational poles of seven asteroids from Lick Observatory adaptive optics images, and of Ceres
Drummond, Jack; Christou, Julian
Seven main belt asteroids, 2 Pallas, 3 Juno, 4 Vesta, 16 Psyche, 87 Sylvia, 324 Bamberga, and 707 Interamnia, were imaged with the adaptive optics system on the 3 m Shane telescope at Lick Observatory in the near infrared, and their triaxial ellipsoid dimensions and rotational poles have been determined with parametric blind deconvolution. In addi…
Cometary cryo-volcanism: Source regions and a model for the UT 2005 June 14 and other mini-outbursts on Comet 9P/Tempel 1
Feldman, Paul D.; A'Hearn, Michael F.; Belton, Michael J. S. +1 more
Data on the UT 2005 June 14 mini-outburst of Comet 9P/Tempel 1 taken from different viewpoints have been examined for morphological differences and parallax. The data were taken with the Hubble Space Telescope (HST), from the Deep Impact (DI) spacecraft, and from the Calar Alto Observatory, Spain. The mini-outburst source region was found to be lo…
On the Relationship between Flux Emergence and CME Initiation
Zhang, Hongqi; Zhang, Mei; Zhang, Yin
We present in this paper a statistical study aimed at understanding the possible relationship between surface magnetic field variation and CME initiation. The three samples studied comprise 189 CME-source regions, 46 active regions, and 15 newly emerging active regions. Both large-scale and small-scale variations of longitudinal magnetic fields of…
X-ray and optical observations of M55 and NGC 6366: evidence for primordial binaries
Lewin, W. H. G.; Verbunt, F.; Pooley, D. +3 more
We present Chandra X-ray Observatory ACIS-S3 X-ray imaging observations and VLT/FORS2 and Hubble Space Telescope optical observations of two low-density Galactic globular clusters; NGC 6366 and M 55. We detect 16 X-ray sources with 0.5-6.0 keV luminosities above L_ {X}= 4 × 1030 erg s-1 within the half-mass radius of M 55, of…
The Long-Term Radiative Evolution of Anomalous X-Ray Pulsar 1E 2259+586 After Its 2002 Outburst
Zhu, Weiwei; Kaspi, Victoria M.; Woods, Peter M. +3 more
We present an analysis of five XMM-Newton observations of the anomalous X-ray pulsar (AXP) 1E 2259+586 taken in 2004 and 2005 during its relaxation following its 2002 outburst. We compare these data with those of five previous XMM-Newton observations taken in 2002 and 2003, and find the observed flux decay is well described by a power law of index…
A Statistical Study on Rotating Sunspots: Polarities, Rotation Directions, and Helicities
Yan, X. L.; Qu, Z. Q.; Xu, C. L.
Observations of white-light images from SOHO MDI, TRACE, Hinode, SOHO MDI magnetograms, and Hinode SP vector magnetograms show sufficient samples of rotating sunspots on the solar photosphere for a statistical study. During the period from 1996 December to 2007 December, after individually checking the active regions in detail, we found 182 measur…