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

TL;DR

This study models Venus's dayglow emissions, highlighting electron impact on CO as the main Cameron band source and comparing predictions with recent SPICAV/Venus Express observations.

Contribution

It provides updated calculations of Venus's dayglow emissions considering different solar activities and cross sections, aligning model predictions with recent observational data.

Findings

Electron impact on CO is the primary Cameron band source.

Overhead intensities vary significantly with solar activity.

Model predictions agree with recent SPICAV observations.

Abstract

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 CO2+ UV doublet emissions are calculated for low, moderate, and high solar activity conditions. Using updated cross sections, the impact of dierent e-CO cross section 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 N2 Vegard-Kaplan UV bands and OI 2972 {\AA} emissions during moderate and high solar activity conditions.