Non-LTE models of Titan's upper atmosphere
1991; IOP Publishing; Volume: 383; Linguagem: Inglês
10.1086/170796
ISSN1538-4357
Autores Tópico(s)Atmospheric Ozone and Climate
Resumoview Abstract Citations (124) References (52) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Non--LTE Models of Titan's Upper Atmosphere Yelle, Roger V. Abstract Models for the thermal structure of Titan's upper atmosphere, between 0.1 mbar and 0.01 nbar are presented. The calculations include non-LTE heating/cooling in the rotation-vibration bands of CH4, C2H2, and C2H6, absorption of solar IR radiation in the near-IR bands of CH4 and subsequent cascading to the nu-4 band of CH4, absorption of solar EUV and UV radiation, thermal conduction and cooling by HCN rotational lines. Unlike earlier models, the calculated exospheric temperature agrees well with observations, because of the importance of HCN cooling. The calculations predict a well-developed mesopause with a temperature of 135-140 K at an altitude of approximately 600 km and pressure of about 0.1 microbar. The mesopause is at a higher pressure than predicted by earlier calculations because non-LTE radiative transfer in the rotation-vibration bands of CH4, C2H2, and C2H6 is treated in an accurate manner. The accuracy of the LTE approximation for source functions and heating rates is discussed. Publication: The Astrophysical Journal Pub Date: December 1991 DOI: 10.1086/170796 Bibcode: 1991ApJ...383..380Y Keywords: Atmospheric Models; Nonequilibrium Thermodynamics; Satellite Atmospheres; Titan; Acetylene; Ethane; Methane; Rotational Spectra; Upper Atmosphere; Vibrational Spectra; Lunar and Planetary Exploration; PLANETS: SATELLITES; PLANETS: SATURN full text sources ADS |
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