UVIS observations of the FUV OI and CO 4P Venus dayglow during the Cassini flyby

作者：Hubert B^*; Gerard J C; Gustin J; Shematovich V I; Bisikalo D V; Stewart A I; Gladstone G R

来源：Icarus, 2010, 207(2): 549-557.

DOI：10.1016/j.icarus.2009.12.029

• Venus, Atmosphere
• Ultraviolet observations
• Aeronomy
• Radiative transfer

We analyze FUV spatially-resolved dayglow spectra obtained at 0.37 nm resolution by the UVIS instrument during the Cassini flyby of Venus. We use a least-squares fit method to determine the brightness of the 01 emissions at 130.4 and 01 135.6 nm, and of the bands of the CO fourth positive system which are dominated by fluorescence scattering. We compare the brightness observed along the UVIS foot track of the two 01 multiplets with that deduced from a model of the excitation of these emissions by photoelectron impact on 0 atoms and resonance scattering of the solar 130.4 nm emission. The large optical thickness 130.4 nm emission is accounted for using a radiative transfer model. The airglow intensities are calculated along the foot track and found to agree with the observed 130.4 nm brightness within similar to 10%. The modeled OI 135.6 nm brightness is also well reproduced by the model. The oxygen density profile of the VTS3 model is found to be consistent with the observations. We find that self-absorption of the (0, v '') bands of the fourth positive emission of CO is important and we derive a CO vertical column of about 6.4 x 10(15) cm(-2) in close agreement with the value provided by the VTS3 empirical atmospheric model.

• 出版日期2010-6