ORBi: Ajello Joseph M. - Titan airglow spectra from the Cassini Ultraviolet Imaging Spectrograph: FUV disk analysis

Reference : Titan airglow spectra from the Cassini Ultraviolet Imaging Spectrograph: FUV disk analysis


	Document type :	Scientific journals : Article
	Discipline(s) :	Physical, chemical, mathematical & earth Sciences : Space science, astronomy & astrophysics
	To cite this reference:	http://hdl.handle.net/2268/128454

Title :	Titan airglow spectra from the Cassini Ultraviolet Imaging Spectrograph: FUV disk analysis
Language :	English
Author, co-author :	Ajello, Joseph M. []
	Gustin, Jacques [Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Physique des atmosphères et des environnements planétaires >]
	Stewart, Ian []
	Larsen, Kristopher []
	Esposito, Larry []
	Pryor, Wayne []
	McClintock, William []
	Stevens, Michael []
	Malone, Charles []
	Dziczek, Darius []
Publication date :	2008
Journal title :	Geophysical Research Letters
Publisher :	American Geophysical Union
Peer reviewed :	Yes (verified by ORBi)
Audience :	International
ISSN :	0094-8276
e-ISSN :	0094-8276
City :	Washington
Country :	DC
Abstract :	[en] We present a spectral analysis of the far ultraviolet (FUV: 1150–1900 A ° ) disk airglow observations of Titan’s atmosphere by the Cassini Ultraviolet Imaging Spectrograph (UVIS). The FUV spectrum consists of emissions from the Lyman-Birge-Hopfield (LBH) band system of N2 excited by photoelectrons (a 1Pg ! X 1Sg+), N I multiplets from solar photodissociative excitation of N2, resonantly scattered solar H Ly-a and sunlight reflected by N2 in the mesosphere-stratosphere and modified by aerosols (e.g.,tholins) and hydrocarbon absorption. Below 1450 A, the strongest emissions arise from H Ly-a with an intensity of 208 Rayleighs (R), LBH bands with an intensity of 43 R, and the N I multiplets with a combined intensity of 16 R. Above 1450 A , most of the UVIS signal is due to reflected sunlight. Mixing ratios of tholins, C2H2, C2H4 and C4H2 have been derived from the reflected sunlight using a Rayleigh scattering model. The derived mixing ratios are in good agreement with Voyager infrared observations and with FUV photochemical models, assuming solar energy deposition above 1450 A occurs near 250 km (Wilson and Atreya, 2004). We also present the first geometric albedo measurement of Titan from 1500–1900 A
Target :	Researchers ; Professionals ; Students
Permalink :	http://hdl.handle.net/2268/128454

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