Reference : The production of Titan's ultraviolet nitrogen airglow
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Space science, astronomy & astrophysics
http://hdl.handle.net/2268/114248
The production of Titan's ultraviolet nitrogen airglow
English
Stevens, Michael H [Space Science Division, Naval Research Laboratory, Washington, D. C., USA]
Gustin, Jacques mailto [Université de Liège - ULg > Département d'astrophys., géophysique et océanographie (AGO) > Physique des atmosphères et des environnements planétaires]
Ajello, Joseph M [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA]
Evans, J Scott [Computational Physics, Inc., Springfield, Virginia, USA]
Meier, R. R. [Department of Physics and Astronomy, George Mason University, Fairfax, Virginia, USA]
Kochenash, Andrew J [Computational Physics, Inc., Springfield, Virginia, USA]
Stephan, Andrew W [Space Science Division, Naval Research Laboratory, Washington, D. C., USA]
Stewart, A Ian F [Laboratory for Atmospheric and Space Physics, University of Colorado at Boulder, Boulder, Colorado, USA]
Esposito, Larry W [Laboratory for Atmospheric and Space Physics, University of Colorado at Boulder, Boulder, Colorado, USA]
McClintock, William E [Laboratory for Atmospheric and Space Physics, University of Colorado at Boulder, Boulder, Colorado, USA]
Holsclaw, Greg [Laboratory for Atmospheric and Space Physics, University of Colorado at Boulder, Boulder, Colorado, USA]
Bradley, E Todd [Department of Physics, University of Central Florida, Orlando, Florida, USA]
Lewis, B. R. [Research School of Physics and Engineering, Australian National University, Canberra, ACT, Australia]
Heays, A. N. [Research School of Physics and Engineering, Australian National University, Canberra, ACT, Australia]
1-May-2011
Journal of Geophysical Research. Space Physics
American Geophysical Union (AGU)
116
05304
Yes (verified by ORBi)
International
0148-0227
Washington
DC
[en] Atmospheric Composition and Structure: Airglow and aurora ; Atmospheric Composition and Structure: Radiation: transmission and scattering ; Atmospheric Composition and Structure: Thermosphere: energy deposition (3369) ; Planetary Sciences: Solar System Objects: Titan ; Atmospheric Composition and Structure: Planetary atmospheres (5210 ; 5405 ; 5704)
[en] The Cassini Ultraviolet Imaging Spectrograph (UVIS) observed Titan's dayside limb in the extreme ultraviolet (EUV) and far ultraviolet (FUV) on 22 June 2009 from a mean distance of 23 Titan radii. These high-quality observations reveal the same EUV and FUV emissions arising from photoelectron excitation and photofragmentation of molecular nitrogen (N[SUB]2[/SUB]) as found on Earth. We investigate both of these solar driven processes with a terrestrial airglow model adapted to Titan and find that total predicted radiances for the two brightest N[SUB]2[/SUB] band systems agree with the observed peak radiances to within 5%. Using N[SUB]2[/SUB] densities constrained from in situ observations by the Ion Neutral Mass Spectrometer on Cassini, the altitude of the observed limb peak of the EUV and FUV emission bands is between 840 and 1060 km and generally consistent with model predictions. We find no evidence for carbon emissions in Titan's FUV airglow in contrast to previous Titan airglow studies using UVIS data. In their place, we identify several vibrational bands from the N[SUB]2[/SUB] Vegard-Kaplan system arising from photoelectron impact with predicted peak radiances in agreement with observations. These Titan UV airglow observations are therefore comprised of emissions arising only from solar processes on N[SUB]2[/SUB] with no detectable magnetospheric contribution. Weaker EUV Carroll-Yoshino N[SUB]2[/SUB] bands within the v′ = 3, 4, and 6 progressions between 870 and 1020 Å are underpredicted by about a factor of five while the (0,1) band near 980 Å is overpredicted by about a factor of three.
http://hdl.handle.net/2268/114248
10.1029/2010JA016284
http://esoads.eso.org/abs/2011JGRA..11605304S

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