Publication Date:
1997-01-31
Description:
Saturn's giant moon Titan has a thick (1.5 bar) nitrogen atmosphere, which has a temperature structure that is controlled by the absorption of solar and thermal radiation by methane, hydrogen, and organic aerosols into which methane is irreversibly converted by photolysis. Previous studies of Titan's climate evolution have been done with the assumption that the methane abundance was maintained against photolytic depletion throughout Titan's history, either by continuous supply from the interior or by buffering by a surface or near surface reservoir. Radiative-convective and radiative-saturated equilibrium models of Titan's atmosphere show that methane depletion may have allowed Titan's atmosphere to cool so that nitrogen, its main constituent, condenses onto the surface, collapsing Titan into a Triton-like frozen state with a thin atmosphere.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Lorenz, R D -- McKay, C P -- Lunine, J I -- New York, N.Y. -- Science. 1997 Jan 31;275(5300):642-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Planetary Sciences, Lunar and Planetary Laboratory, University of Arizona, Tucson 85721, USA.rlorenz@pl.arizona.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/9005844" target="_blank"〉PubMed〈/a〉
Keywords:
Atmosphere
;
*Evolution, Planetary
;
*Extraterrestrial Environment
;
*Methane
;
*Nitrogen
;
Photolysis
;
*Saturn
;
Temperature
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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