title: Release of volatiles from a possible cryovolcano from near-infrared imaging of Titan.
abstract: Titan is the only satellite in our Solar System with a dense atmosphere. The surface pressure is 1.5 bar (ref. 1) and, similar to the Earth, N2 is the main component of the atmosphere. Methane is the second most important component, but it is photodissociated on a timescale of 10(7) years (ref. 3). This short timescale has led to the suggestion that Titan may possess a surface or subsurface reservoir of hydrocarbons to replenish the atmosphere. Here we report near-infrared images of Titan obtained on 26 October 2004 by the Cassini spacecraft. The images show that a widespread methane ocean does not exist; subtle albedo variations instead suggest topographical variations, as would be expected for a more solid (perhaps icy) surface. We also find a circular structure approximately 30 km in diameter that does not resemble any features seen on other icy satellites. We propose that the structure is a dome formed by upwelling icy plumes that release methane into Titan's atmosphere.
authors.affiliation: Laboratoire de Planétologie et Géodynamique, UMR CNRS 6112, Université de Nantes, Nantes, 44100, France. Christophe.Sotin@univ-nantes.fr
authors.forename: C
authors.initials: C
authors.lastname: Sotin
authors.forename: R
authors.initials: R
authors.lastname: Jaumann
authors.forename: B J
authors.initials: BJ
authors.lastname: Buratti
authors.forename: R H
authors.initials: RH
authors.lastname: Brown
authors.forename: R N
authors.initials: RN
authors.lastname: Clark
authors.forename: L A
authors.initials: LA
authors.lastname: Soderblom
authors.forename: K H
authors.initials: KH
authors.lastname: Baines
authors.forename: G
authors.initials: G
authors.lastname: Bellucci
authors.forename: J-P
authors.initials: JP
authors.lastname: Bibring
authors.forename: F
authors.initials: F
authors.lastname: Capaccioni
authors.forename: P
authors.initials: P
authors.lastname: Cerroni
authors.forename: M
authors.initials: M
authors.lastname: Combes
authors.forename: A
authors.initials: A
authors.lastname: Coradini
authors.forename: D P
authors.initials: DP
authors.lastname: Cruikshank
authors.forename: P
authors.initials: P
authors.lastname: Drossart
authors.forename: V
authors.initials: V
authors.lastname: Formisano
authors.forename: Y
authors.initials: Y
authors.lastname: Langevin
authors.forename: D L
authors.initials: DL
authors.lastname: Matson
authors.forename: T B
authors.initials: TB
authors.lastname: McCord
authors.forename: R M
authors.initials: RM
authors.lastname: Nelson
authors.forename: P D
authors.initials: PD
authors.lastname: Nicholson
authors.forename: B
authors.initials: B
authors.lastname: Sicardy
authors.forename: S
authors.initials: S
authors.lastname: LeMouelic
authors.forename: S
authors.initials: S
authors.lastname: Rodriguez
authors.forename: K
authors.initials: K
authors.lastname: Stephan
authors.forename: C K
authors.initials: CK
authors.lastname: Scholz
mesh_terms: D001272:Atmosphere / Q000737:chemistry; D005118:Extraterrestrial Environment / Q000737:chemistry*; D005740:Gases / Q000032:analysis* / Q000737:chemistry; D005843:Geography; D006838:Hydrocarbons / Q000032:analysis / Q000737:chemistry; D007053:Ice / Q000032:analysis*; D007259:Infrared Rays; D008697:Methane / Q000032:analysis / Q000737:chemistry; D016081:Moon; D010781:Photography; D018539:Saturn; D018531:Spacecraft
chemical_list: D005740:Gases; D006838:Hydrocarbons; D007053:Ice; D008697:Methane