CO Cameron band and CO₂⁺ UV doublet emissions in the dayglow of Venus: role of CO in the Cameron band production

Abstract

[1] The present study deals with the model calculations of CO Cameron band and CO₂⁺ ultraviolet doublet emissions in the dayglow of Venus. The overhead and limb intensities of CO Cameron band and inline image UV doublet emissions are calculated for low, moderate, and high solar activity conditions. Using updated cross sections, the impact of different e-CO cross sections for Cameron band production is estimated. The electron impact on CO is the major source mechanism of Cameron band, followed by electron and photon impact dissociation of CO₂. The overhead intensities of CO Cameron band and CO₂⁺ UV doublet emissions are about a factor of 2 higher in solar maximum than those in solar minimum condition. The effect of solar EUV flux models on the emission intensity is ∼30–40% in solar minimum condition and ∼2–10% in solar maximum condition. At the altitude of emission peak (∼135 km), the model predicted limb intensity of CO Cameron band and CO₂⁺ UV doublet emissions in moderate (F10.7=130) solar activity condition is about 2400 and 300 kR, respectively, which is in agreement with the very recently published SPICAV/Venus Express observation. The model limb intensity profiles of CO Cameron band and CO₂⁺ UV doublet are compared with SPICAV observation. We also calculated intensities of N2Vegard-Kaplan UV bands and O I 2972 Å emissions during moderate and high solar activity conditions.