First Observation of the Oxygen 630 nm Emission in the Martian Dayglow

Abstract

The first Martian dayglow observations were collected with the ultraviolet spectrometers on board Mariner 6, 7, and 9 flown to Mars in the early 1970s (Barth, 1974). They identified the presence of a series of oxygen and carbon lines and molecular bands originating from CO and CO 2 + . They obtained limb profiles of the strongest emissions. High quality extreme ultraviolet disk spectra were collected with the Hopkins Ultraviolet Telescope by Feldman et al. (2000). Later, limb observations with the SPICAM instrument on board Mars Express identified N 2 Vegard-Kaplan emissions in the middle ultraviolet (Leblanc et al., 2007). A major step forward was made with the Imaging Ultraviolet Spectrograph (IUVS) spectral imager on board the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft, which has collected a wealth of ultraviolet limb scans (Jain et al., 2015).The possible presence of visible dayglow emissions in the Martian dayglow was investigated by Fox and Dalgarno (1979) who modeled the sources and sinks of O( 1 S) metastable atoms that produce emission of the green line and trans-auroral emissions at 555.7 and 297.2 nm respectively. They also predicted the

The Mars Oxygen Visible Dayglow: A Martian Year of NOMAD/UVIS Observations

“…This result is in very good agreement with previous NOMAD/UVIS results from Gérard et al. (2021), based on a smaller number of observation than this study. Note that this average limb profile mixes up all latitudes, longitudes, SZA up to 70° and seasons.…”

“…The presence of the second doublet component both corroborates the initial identification by Gérard et al. (2021) and confirms the constancy of the value of the ratio of the doublet components in a physical and chemical planetary environment different from the Earth's conditions.…”

“…These values are higher than those of Gérard et al. (2021) because the average Sun‐Mars distance is smaller in this extended database than in the original report when the observations were made closer to aphelion. If the mesospheric scale height is extrapolated above 110 km and subtracted from the total signal (to remove the production of the upper peak caused by the photodissociation of CO 2 by solar Lyman‐α photons), the secondary peak (generated by the interaction of extreme ultraviolet solar photons with CO 2 ) brightness reaches 22 kR.…”

Density and Temperature of the Upper Mesosphere and Lower Thermosphere of Mars Retrieved From the OI 557.7 nm Dayglow Measured by TGO/NOMAD

“…The forward model F(x) is calculated by the 1-dimensional photochemical model for airglow emission, named "Photochemical Airglow Mars" (PAM) model (Gérard et al, 2019;Gkouvelis et al, 2018;Gkouvelis, Gérard, Ritter et al, 2020;Ritter et al, 2019), which successfully matched the Ultraviolet lines of O( 1 S) 297.2 nm, CO Cameron bands, CO 2 + UV doublet as well as the green and red optical emission lines at 557 and 630 nm that were discovered at the atmosphere of Mars (Gérard et al, 2020(Gérard et al, , 2021. This model was originally developed for the oxygen ultraviolet airglow emission of 297.2 nm.…”

Photodissociation Rate, Excess Energy, and Kinetic Total Energy Release for the Photolysis of H2O Producing O(1S) by Solar UV Radiation Field

“…Forbidden atomic oxygen emission lines at 557.8 and 630.0/ 636.4 nm are ubiquitous in terrestrial atmospheres and cometary comae (Slanger et al 2001(Slanger et al , 2006Feldman et al 2004;Cosby et al 2006;Gérard et al 2021). These lines are diagnostics of chemistry in terrestrial atmospheres and cometary comae.…”