On Mars, atomic oxygen controls the carbon dioxide radiative cooling of the upper atmosphere and the presence of an ozone layer near the poles. To remotely probe meridional transport of O atoms from the summer to the winter hemisphere and the descending flow in the winter polar regions, the O2 Herzberg II atmospheric emission could be used as a proxy. This emission is quite weak on Earth’s nightside, but it is prominent in the Venus night airglow, and it has not previously been observed on Mars. Here we report the limb detection of the O2 Herzberg II visible bands in the Mars nightglow with the NOMAD ultraviolet–visible spectrometer onboard the European Space Agency’s Trace Gas Orbiter. The emission layer reaches up to hundreds of kilorayleighs in the limb viewing geometry. It is mainly located between 40 km and 60 km at high latitudes during the winter season, consistent with three-body recombination of oxygen atoms. This O2 nightglow should be observable from a Martian orbiter as well as from the Martian surface with the naked eye under clear sky conditions. These observations pave the way to future global observations of the Martian atmospheric circulation with simpler lower-cost instrumentation.
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The NOMAD-UVIS spectra can be downloaded from ESA’s SA archives at https://archives.esac.esa.int/psa/#!Table%20View/NOMAD=instrument (select UVIS from the list of instruments and ‘Level 3 Calibrated’ from the processing level). Observed limb intensities and model calculations supporting Fig. 4 are available from BIRA-IASB repository at https://doi.org/10.18758/71021084 or from the corresponding author upon reasonable request.
Barth, C. A. et al. Mariner 6 and 7 ultraviolet spectrometer experiment: upper atmosphere data. J. Geophys. Res. 76, 2213–2227 (1971).
Gérard, J. C. et al. Detection of green line emission in the dayside atmosphere of Mars from NOMAD-TGO observations. Nat. Astron. 4, 1049–1052 (2020).
Gérard, J. C. et al. First observation of the oxygen 630 nm emission in the Martian dayglow. Geophys. Res. Lett. 48, e2020GL092334 (2021).
Aoki, S. et al. Density and temperature of the upper mesosphere and lower thermosphere of Mars retrieved from the O i 557.7 nm dayglow measured by TGO/NOMAD. J. Geophys. Res. 127, e2022JE007206 (2022).
Soret, L. et al. The Mars oxygen visible dayglow: a Martian year of NOMAD/UVIS observations. J. Geophys. Res. 127, e2022JE007220 (2022).
Schneider, N. M. et al. Imaging of Martian circulation patterns and atmospheric tides through MAVEN/IUVS nightglow observations. J. Geophys. Res. 125, e2019JA027318 (2020).
Bertaux, J. L., Gondet, B., Lefèvre, F., Bibring, J. P. & Montmessin, F. First detection of O2 1.27 μm nightglow emission at Mars with OMEGA/MEX and comparison with general circulation model predictions. J. Geophys. Res. 117, E00J04 (2012).
Fedorova, A. et al. The O2 nightglow in the martian atmosphere by SPICAM onboard of Mars-Express. Icarus 219, 596–608 (2012).
Clancy, R. T. et al. Extensive MRO CRISM observations of 1.27 μm O2 airglow in Mars polar night and their comparison to MRO MCS temperature profiles and LMD GCM simulations. J. Geophys. Res. 117, E00J10 (2012).
Clancy, R. T. et al. First detection of Mars atmospheric hydroxyl: CRISM near-IR measurement versus LMD GCM simulation of OH Meinel band emission in the Mars polar winter atmosphere. Icarus 226, 272–281 (2013).
Patel, M. R. et al. NOMAD spectrometer on the ExoMars trace gas orbiter mission: part 2—design, manufacturing, and testing of the ultraviolet and visible channel. Appl. Opt. 56, 2771–2782 (2017).
Vandaele, A. C. et al. An integrated suite of three spectrometers for the ExoMars trace gas mission: technical description, science objectives and expected performance. Space Sci. Rev. 214, 1–47 (2018).
López-Valverde et al. Investigations of the Mars upper atmosphere with ExoMars Trace Gas Orbiter. Space Sci. Rev. 214, 29 (2018).
Krupenie, P. H. The spectrum of molecular oxygen. J. Phys. Chem. Ref. Data 1, 423–534 (1972).
Krasnopolsky, V. A. in Venus (eds Hunten D. M. et al.) 459–483 (Univ. Arizona Press, 1983).
Lawrence, G. M., Barth, C. A. & Argabright, V. Excitation of the Venus night airglow. Science 195, 573–574 (1977).
Slanger, T. G. & Copeland, R. A. Energetic oxygen in the upper atmosphere and the laboratory. Chem. Rev. 103, 4731–4766 (2003).
Bougher, S. W. & Borucki, W. J. Venus O2 visible and IR nightglow: implications for lower thermosphere dynamics and chemistry. J. Geophys. Res. 99, 3759–3776 (1994).
Krasnopolsky, V. A. Excitation of the oxygen nightglow on the terrestrial planets. Planet. Space Sci. 59, 754–766 (2011).
Bougher, S. W., Hunten, D. M. & Roble, R. G. CO2 cooling in terrestrial planet thermospheres. J. Geophys. Res. 99, 14609–14622 (1994).
Montmessin, F. & Lefèvre, F. Transport-driven formation of a polar ozone layer on Mars. Nat. Geosci. 6, 930–933 (2013).
Forget, F. et al. Improved general circulation models of the Martian atmosphere from the surface to above 80 km. J. Geophys. Res. 104, 24155–24175 (1999).
Omholt, A. The Optical Aurora (Springer, 1971); https://doi.org/10.1007/978-3-642-46269-6
Lilensten, J. Prediction of blue, red and green aurorae at Mars. Planet. Space Sci. 115, 48–56 (2015).
Willame, Y. et al. Calibration of the NOMAD-UVIS data. Planet. Space Sci. 218, 105504 (2022).
García Muñoz, A., Mills, F. P., Slanger, T. G., Piccioni, G. & Drossart, P. Visible and near‐infrared nightglow of molecular oxygen in the atmosphere of Venus. J. Geophys. Res. 114, E12002 (2009).
García Muñoz, A. et al. Limb imaging of the Venus O2 visible nightglow with the Venus Monitoring Camera. Geophys. Res. Lett. 40, 2539–2543 (2013).
Gérard, J. C., Soret, L., Migliorini, A. & Piccioni, G. Oxygen nightglow emissions of Venus: vertical distribution and collisional quenching. Icarus 223, 602–608 (2013).
Migliorini, A. et al. The characteristics of the O2 Herzberg II and Chamberlain bands observed with VIRTIS/Venus Express. Icarus 223, 609–614 (2013).
Smith, G. P. & Robertson, R. Temperature dependence of oxygen atom recombination in nitrogen after ozone photolysis. Chem. Phys. Lett. 458, 6–10 (2008).
Nair, H., Allen, M., Anbar, A. D., Yung, Y. L. & Clancy, R. T. A photochemical model of the Martian atmosphere. Icarus 111, 124–150 (1994).
Millour, E. et al. The Mars Climate Database (Version 6.1). EPSC Abstr. 16, EPSC2022-786 (2022).
B.H. is research associate of the Belgian Fund for Scientific Research (FNRS). ExoMars is a space mission of ESA and Roscosmos. The NOMAD experiment is led by the IASB-BIRA, assisted by co-principal-investigator teams from Spain (IAA-CSIC), Italy (INAF-IAPS) and the United Kingdom (The Open University). This project acknowledges funding from BELSPO, with the financial and contractual coordination by the ESA Prodex Office (PEA grant numbers 4000140863, 4000121493 and 4000129683). M.A.L.-V. was supported by grant number PGC2018-101836-B-100 (MCIU/AEI/FEDER, EU) and CEX2021-001131-S funded by MCIN/AEI/10.13039/501100011033. We also acknowledge support from the UK Space Agency through grant numbers ST/V002295/1, ST/V005332/1, ST/Y000234/1 and ST/X006549/1’. We thank the ESA TGO team and its project scientists H. Svedhem and C. Wilson for supporting these observations.
The authors declare no competing interests.
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Gérard, JC., Soret, L., Thomas, I.R. et al. Observation of the Mars O2 visible nightglow by the NOMAD spectrometer onboard the Trace Gas Orbiter. Nat Astron (2023). https://doi.org/10.1038/s41550-023-02104-8