Fulchignoni M, Ferri F, Angrilli F, Ball AJ, Bar-Nun A, Barucci MA, Bettanini C, Bianchini G, Borucki W, Colombatti G, Coradini M, Coustenis A, Debei S, Falkner P, Fanti G, Flamini E, Gaborit V, Grard R, Hamelin M, Harri AM, Hathi B, Jernej I, Leese MR, Lehto A, Lion Stoppato PF, López-Moreno JJ, Mäkinen T, McDonnell JAM, McKay CP, Molina-Cuberos G, Neubauer FM, Pirronello V, Rodrigo R, Saggin B, Schwingenschuh K, Seiff A, Simões F, Svedhem H, Tokano T, Towner MC, Trautner R, Withers P, Zarnecki JC. In situ measurements of the physical characteristics of Titan's environment.
Nature 2005;
438:785-91. [PMID:
16319827 DOI:
10.1038/nature04314]
[Citation(s) in RCA: 545] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2005] [Accepted: 10/11/2005] [Indexed: 11/08/2022]
Abstract
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 the temperature and density profiles, as determined by the Huygens Atmospheric Structure Instrument (HASI), from an altitude of 1,400 km down to the surface. In the upper part of the atmosphere, the temperature and density were both higher than expected. There is a lower ionospheric layer between 140 km and 40 km, with electrical conductivity peaking near 60 km. We may also have seen the signature of lightning. At the surface, the temperature was 93.65 +/- 0.25 K, and the pressure was 1,467 +/- 1 hPa.
Collapse