Detection of the Nitric Oxide Dayglow on Mars by MAVEN/IUVS

Stevens, M. H.; Siskind, David E.; Evans, J. S.; Fox, Jane L.; Deighan, Justin; Jain, Sonal; Schneider, Nicholas M.

doi:10.1029/2019je005945

Cited by 16 publications

(36 citation statements)

References 63 publications

(114 reference statements)

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“…At relatively low altitudes, the odd N abundances that we derive are in general consistent with the model results of Fox () (see their Figure 11) under similar solar activity conditions. The low‐altitude NO abundances are also consistent with the IUVS results of (Stevens, ) (see their Figure 6) but are a factor of 10 lower than those directly extracted from the NGIMS measurements atM/Z=30 Da (the molecular mass of NO) during DD2 (see Mahaffy, , their Figure 2), which, as addressed above, are subject to strong wall contamination. In contrast, the odd N abundances at high altitudes are remarkably different from existing model results.…”

Section: No Abundance Under Chemical Equilibriumsupporting

confidence: 84%

“…Using instead a lower limit rate coefficient of1×10 −10 cm 3 s −1 for both reactions (Roche et al, ) would reduce the derived NO densities at all times by more than an order of magnitude, as given by the red dashed line in Figure a, but these densities are still way too high. In practice, the rate coefficients have to be unrealistically smaller than1×10 −11 cm 3 s −1 to be compatible with the IUVS NO measurements (Stevens et al, ).…”

Section: Discussion: the Role Of Hno+ Chemistrymentioning

confidence: 84%

“…The NO abundances in the Martian thermosphere are also available from the MAVEN Neutral Gas and Ion Mass Spectrometer (NGIMS) measurements (Mahaffy, ), similar to the early mass spectrometer measurements made onboard the Vikings 1 and 2 (Nier & McElroy, , ). However, the NGIMS‐based NO abundances are substantially higher than the IUVS‐based results, which has been attributed to the instrument bias caused by the recombination of atomic N and O on the NGIMS antechamber walls (Stevens, ). Such an instrumental effect has also been speculated to strongly affect the NGIMS‐based O 2 densities (Stone et al, ) and is well known to occur on other mass spectrometers with a similar design (e.g., Cui et al, ).…”

Section: Introductionmentioning

confidence: 91%

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Nitric Oxide Abundance in the Martian Thermosphere and Its Diurnal Variation

Cui

Ren

et al. 2020

Geophysical Research Letters

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As an important species of the Martian thermosphere, NO is chemically and radiatively active. However, its abundance is poorly constrained due to difficulties in both remote sensing and in situ measurements. In this study, we use the Neutral Gas and Ion Mass Spectrometer measurements made onboard the Mars Atmosphere and Volatile Evolution to derive the N( 4 S), N( 2 D), and NO abundances in the Martian thermosphere based on time-dependent odd N chemistry. At a reference altitude of 160 km, our calculations suggest that the NO abundance is maximized in the afternoon whereas the N( 4 S) and N( 2 D) abundances maximized in the morning, both driven by the variation of the ambient N 2 mixing ratio. The difference in chemical loss time scale implies a strong diurnal variation for NO and N( 2 D) but a weak variation for N( 4 S).Plain Language Summary NO is usually regarded as a good tracer of energy input into the upper atmospheres of terrestrial planets. On Mars, NO is mainly produced via the reaction of atomic N in the excited state with ambient CO 2 and lost via the reaction with atomic N in the ground state. Existing investigations of NO abundance in the Martian upper atmosphere are extremely limited due to difficulties in both remote sensing and in situ measurements. In this study, we propose a useful approach to determine the NO abundance on both the dayside and nightside of Mars by combining our knowledge of the odd N chemistry with available neutral and ion density measurements of relevant chemical reactants. On the dayside, we find the NO abundance to be maximized late in the afternoon, which is driven by the variation of N 2 mixing ratio in the background atmosphere. Our analysis also allows the diurnal variation of NO to be explored for the first time, revealing a strong day-night difference by 3 orders of magnitude. This is caused by the fast depletion of NO on the nightside where its production source drops to a minimum level in the absence of solar radiation.

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Section: No Abundance Under Chemical Equilibriumsupporting

confidence: 84%

Section: Discussion: the Role Of Hno+ Chemistrymentioning

confidence: 84%

Section: Introductionmentioning

confidence: 91%

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Nitric Oxide Abundance in the Martian Thermosphere and Its Diurnal Variation

Cui

Ren

et al. 2020

Geophysical Research Letters

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“…Although nightglow measurements were not part of the MAVEN mission requirements, observations have proven to be straightforward and valuable. These nightglow NO emissions are not to be confused with dayside NO emissions (Stevens et al, 2019) which originate through a different physical process.…”

Section: Introductionmentioning

confidence: 98%

Imaging of Martian Circulation Patterns and Atmospheric Tides Through MAVEN/IUVS Nightglow Observations

et al. 2020

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We report results from a study of two consecutive Martian years of imaging observations of nitric oxide ultraviolet nightglow by the Imaging Ultraviolet Spectrograph (IUVS) on the Mars Atmosphere and Volatile Evolution (MAVEN) mission spacecraft. The emission arises from recombination of N and O atoms in Mars' nightside mesosphere. The brightness traces the reaction rate as opposed to the abundance of constituents, revealing where circulation patterns concentrate N and O and enhance recombination. Emissions are brightest around the winter poles, with equatorial regions brightening around the equinoxes. These changes offer clear evidence of circulation patterns transitioning from a single cross‐equatorial cell operating during solstice periods to more symmetric equator‐to‐poles circulation around the equinoxes. Prominent atmospheric tides intensify the emissions at different longitudes, latitude ranges, and seasons. We find a strong eastward‐propagating diurnal tide (DE2) near the equator during the equinoxes, with a remarkably bright spot narrowly confined near (0°, 0°). Wave features at the opposite winter poles are dissimilar, reflecting different circulation patterns at perihelion versus aphelion. LMD‐MGCM simulations agree with the patterns of most observed phenomena, confirming that the model captures the dominant physical processes. At the south winter pole, however, the model fails to match a strong wave‐1 spiral feature. Observed brightnesses exceed model predictions by a factor of 1.9 globally, probably due to an underestimation of the dayside production of N and O atoms. Further study of discrepancies between the model and observations offers opportunities to improve our understanding of chemical and transport processes controlling the emission.

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“…For Mars, a typical dayglow spectrum in the ultraviolet (UV) region includes the Cameron band, the fourth positive band, the ultraviolet doublet (UVD), the Fox-Duffendack-Barker band, and several distinctive emission lines from atomic , , and (Barth et al, 1971;Stewart, 1972;Stewart et al, 1972). More recently, additional faint emission features, such as the Vegard-Kaplan band, the γ band, and the first negative band, have been identified (Leblanc et al, 2006;Jain et al, 2015;Stevens et al, 2015Stevens et al, , 2019. Existing analyses suggest that these dayglow emission features are mostly produced by either photon or photoelectron impact excitation (Fox and Dalgarno, 1979;Fox, 1992).…”

Section: Introductionmentioning

confidence: 99%