Search Publications
Episodic outgassing as the origin of atmospheric methane on Titan
Sotin, Christophe; Lunine, Jonathan I.; Tobie, Gabriel
Saturn's largest satellite, Titan, has a massive nitrogen atmosphere containing up to 5 per cent methane near its surface. Photochemistry in the stratosphere would remove the present-day atmospheric methane in a few tens of millions of years. Before the Cassini-Huygens mission arrived at Saturn, widespread liquid methane or mixed hydrocarbon seas …
Methane drizzle on Titan
Neubauer, Fritz M.; McKay, Christopher P.; Tokano, Tetsuya +4 more
Saturn's moon Titan shows landscapes with fluvial features suggestive of hydrology based on liquid methane. Recent efforts in understanding Titan's methane hydrological cycle have focused on occasional cloud outbursts near the south pole or cloud streaks at southern mid-latitudes and the mechanisms of their formation. It is not known, however, if …
Diapir-induced reorientation of Saturn's moon Enceladus
Nimmo, Francis; Pappalardo, Robert T.
Enceladus is a small icy satellite of Saturn. Its south polar region consists of young, tectonically deformed terrain and has an anomalously high heat flux. This heat flux is probably due to localized tidal dissipation within either the ice shell or the underlying silicate core. The surface deformation is plausibly due to upwelling of low-density …
A regular period for Saturn's magnetic field that may track its internal rotation
Russell, C. T.; Dougherty, M. K.; Smith, E. J. +1 more
The rotation rate of a planet is one of its fundamental properties. Saturn's rotation, however, is difficult to determine because there is no solid surface from which to time it, and the alternative `clock'-the magnetic field-is nearly symmetrically aligned with the rotation axis. Radio emissions, thought to provide a proxy measure of the rotation…
Methane storms on Saturn's moon Titan
Hueso, R.; Sánchez-Lavega, A.
The presence of dry fluvial river channels and the intense cloud activity in the south pole of Titan over the past few years suggest the presence of methane rain. The nitrogen atmosphere of Titan therefore appears to support a methane meteorological cycle that sculptures the surface and controls its properties. Titan and Earth are the only worlds …
Titan Radar Mapper observations from Cassini's T3 fly-by
Stiles, B.; Kelleher, K.; Callahan, P. +32 more
Cassini's Titan Radar Mapper imaged the surface of Saturn's moon Titan on its February 2005 fly-by (denoted T3), collecting high-resolution synthetic-aperture radar and larger-scale radiometry and scatterometry data. These data provide the first definitive identification of impact craters on the surface of Titan, networks of fluvial cha…
100-metre-diameter moonlets in Saturn's A ring from observations of ‘propeller’ structures
Dones, Luke; Porco, Carolyn C.; Hedman, Matthew M. +5 more
Saturn's main rings are composed predominantly of water-ice particles ranging between about 1centimetre and 10metres in radius. Above this size range, the number of particles drops sharply, according to the interpretation of spacecraft and stellar occultations. Other than the gap moons Pan and Daphnis (the provisional name of S/2005 S1), which hav…
Anti-planetward auroral electron beams at Saturn
Livi, S.; Krupp, N.; Dougherty, M. K. +10 more
Strong discrete aurorae on Earth are excited by electrons, which are accelerated along magnetic field lines towards the planet. Surprisingly, electrons accelerated in the opposite direction have been recently observed. The mechanisms and significance of this anti-earthward acceleration are highly uncertain because only earthward acceleration was t…
The sequestration of ethane on Titan in smog particles
Hunten, D. M.
Saturn's largest satellite, Titan, has a dense atmosphere of nitrogen with a few per cent of methane. At visible wavelengths its surface is hidden by dense orange-brown smog, which is produced in the stratosphere by photochemical reactions following the dissociation of methane by solar ultraviolet light. The most abundant of the products of these …
Astrochemistry: Complex organic matter in Titan's aerosols? (Reply)
Steller, M.; Atreya, S. K.; Owen, T. +19 more
Biemann et al. calls into question our preliminary interpretations of our experimental results. A comparison of laboratory and flight measurements should settle the uncertainties he raises. In addition to evaluating instrumental characteristics such as the 'piston effect', a technique we used for injecting oven-gas content for gas chromatography-m…