Titan airglow spectra from Cassini Ultraviolet Imaging Spectrograph (UVIS): EUV analysis

被引：45

作者：

Ajello, Joseph M. ^{[1
]}

Stevens, Michael H. ^{[4
]}

Stewart, Ian ^{[2
]}

Larsen, Kristopher ^{[2
]}

Esposito, Larry ^{[2
]}

Colwell, Josh ^{[2
]}

McClintock, William ^{[2
]}

Holsclaw, Greg ^{[2
]}

Gustin, Jacques ^{[2
]}

Pryor, Wayne ^{[3
]}

机构：

[1] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA

[2] Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80303 USA

[3] Cent Arizona Coll, Dept Sci, Coolidge, AZ 85228 USA

[4] USN, Res Lab, Div Space Sci, Washington, DC 20375 USA

来源：

GEOPHYSICAL RESEARCH LETTERS | 2007年 / 34卷 / 24期

关键词：

D O I：

10.1029/2007GL031555

中图分类号：

P [天文学、地球科学];

学科分类号：

07 ;

摘要：

We present the first UV airglow observations of Titan's atmosphere by the Ultraviolet Imaging Spectrograph (UVIS) on Cassini. Using one spectral channel in the EUV from 561-1182 angstrom and one in the FUV from 1115-1913 angstrom, UVIS observed the disk on 13 December, 2004 at low solar activity. The EUV spectrum consists of three band systems of N(2) (b (1)Pi(u), b' (1)Sigma(+)(u), c'(4) (1)Sigma(+)(u) -> X(1)Sigma(+)(g)), while the FUV spectrum consists of one (a (1)Pi(g) -> X (1)Sigma(+)(g)). Both the EUV and FUV spectra contain many NI and N II multiplets that are produced primarily by photodissociative ionization. Spectral intensities of the N(2) c'(4) (1)Sigma(+)(u)(v' = 0) -> X (1)Sigma(+)(g)(v '' = 0 - 2) progression from 950 - 1010 angstrom are resolved for the first time. The UVIS observations reveal that the c'(4) (1)Sigma(+)(u)(0) -> X(1)Sigma(+)(g) (0) vibrational band near 958 angstrom is weak and undetectable, and that N I multiplets near 953.2 and 964.5 angstrom are present instead. Magnetospheric particle excitation may be weak or sporadic, since the nightside EUV spectrum on this orbit shows no observable nitrogen emission features and only H Ly-beta.

引用

页数：5

共 27 条

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