Search Publications
The abundances of constituents of Titan's atmosphere from the GCMS instrument on the Huygens probe
Israel, G.; Atreya, S. K.; Lunine, J. I. +15 more
Saturn's largest moon, Titan, remains an enigma, explored only by remote sensing from Earth, and by the Voyager and Cassini spacecraft. The most puzzling aspects include the origin of the molecular nitrogen and methane in its atmosphere, and the mechanism(s) by which methane is maintained in the face of rapid destruction by photolysis. The Huygens…
In situ measurements of the physical characteristics of Titan's environment
Neubauer, F. M.; Rodrigo, R.; Barucci, M. A. +40 more
On the basis of previous ground-based and fly-by information, we knew that Titan's atmosphere was mainly nitrogen, with some methane, but its temperature and pressure profiles were poorly constrained because of uncertainties in the detailed composition. The extent of atmospheric electricity (`lightning') was also hitherto unknown. Here we report t…
Rain, winds and haze during the Huygens probe's descent to Titan's surface
Keller, H. U.; Küppers, M.; Thomas, N. +37 more
The irreversible conversion of methane into higher hydrocarbons in Titan's stratosphere implies a surface or subsurface methane reservoir. Recent measurements from the cameras aboard the Cassini orbiter fail to see a global reservoir, but the methane and smog in Titan's atmosphere impedes the search for hydrocarbons on the surface. Here we report …
Titan's internal structure inferred from a coupled thermal-orbital model
Sotin, Christophe; Lunine, Jonathan I.; Tobie, Gabriel +2 more
Through coupled thermal and orbital calculations including a full description of tidal dissipation, heat transfer and the H 2O sbnd NH 3 phase diagram, we propose a model for the internal structure and composition of Titan testable with Cassini-Huygens measurements. The high value of Titan's orbital eccentricity provides a st…
The vertical profile of winds on Titan
Plettemeier, D.; Gurvits, L. I.; Pogrebenko, S. V. +12 more
One of Titan's most intriguing attributes is its copious but featureless atmosphere. The Voyager 1 fly-by and occultation in 1980 provided the first radial survey of Titan's atmospheric pressure and temperature and evidence for the presence of strong zonal winds. It was realized that the motion of an atmospheric probe could be used to study the wi…
Possibilities for methanogenic life in liquid methane on the surface of Titan
McKay, C. P.; Smith, H. D.
Photochemically produced compounds on Titan, principally acetylene, ethane and organic solids, would release energy when consumed with atmospheric hydrogen, at levels of 334, 57, and 54 kJ mol -1, respectively. On Earth methanogenic bacteria can survive on this energy level. Here we speculate on the possibility of widespread methanogeni…
A soft solid surface on Titan as revealed by the Huygens Surface Science Package
Banaszkiewicz, Marek; Zarnecki, John C.; Lorenz, Ralph D. +23 more
The surface of Saturn's largest satellite-Titan-is largely obscured by an optically thick atmospheric haze, and so its nature has been the subject of considerable speculation and discussion. The Huygens probe entered Titan's atmosphere on 14 January 2005 and descended to the surface using a parachute system. Here we report measurements made just a…
Radial variations in the Io plasma torus during the Cassini era
Delamere, P. A.; Bagenal, F.; Steffl, A.
A radial scan through the midnight sector of the Io plasma torus was made by the Cassini Ultraviolet Imaging Spectrograph on 14 January 2001, shortly after closest approach to Jupiter. From these data, Steffl et al. (2004a) derived electron temperature, plasma composition (ion mixing ratios), and electron column density as a function of radius fro…
Biologically Enhanced Energy and Carbon Cycling on Titan?
Grinspoon, David H.; Schulze-Makuch, Dirk
With the Cassini-Huygens Mission in orbit around Saturn, the large moon Titan, with its reducing atmosphere, rich organic chemistry, and heterogeneous surface, moves into the astrobiological spotlight. Environmental conditions on Titan and Earth were similar in many respects 4 billion years ago, the approximate time when life originated on Earth. …
Titan atmosphere database
Lebonnois, S.; Rannou, P.; Luz, D. +1 more
We have developed in the last decade a two-dimensional version of the Titan global circulation model LMDZ. This model accounts for multiple coupling occuring on Titan between dynamics, haze, chemistry and radiative transfer. It was successful at explaining many observed features related to atmosphere state (wind, temperature), haze structure and c…