Current understanding of the aeronomy of Mars

Nagy, Andrew F.; Grebowsky, J. M.

doi:10.1186/s40562-015-0019-y

Cited by 4 publications

(4 citation statements)

References 29 publications

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“…The wave-like structures can be clearly found in the temperature profile in Figure 5c, which implies that the atmospheric wave activities are rich in Mars atmosphere, as their induced oscillations seen in Figure 4. Mars's ionosphere below 200 km is in photochemical equilibrium and depends on the solar zenith angle [21][22][23][24]. The solar zenith angle of the RO event is about 87.7 • as mentioned above, which means that the light penetrates a long distance in the atmosphere and its ionizing ability becomes weak.…”

Section: Mars Atmospheric Profilesmentioning

confidence: 98%

First Observations of Mars Atmosphere and Ionosphere with Tianwen-1 Radio-Occultation Technique on 5 August 2021

Song

et al. 2022

Remote Sensing

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The radio-occultation technique can provide vertical profiles of planetary ionospheric and atmospheric parameters, which merit the planetary-climate and space-weather scientific research so far. The Tianwen-1 one-way single-frequency radio-occultation technique was developed to retrieve Mars ionospheric and atmospheric parameters. The first radio-occultation event observation experiment was conducted on 5 August 2021. The retrieved excess Doppler frequency, bending angle, refractivity, electron density, neutral mass density, pressure and temperature profiles are presented. The Mars ionosphere M1 (M2) layer peak height is at 140 km (105 km) with a peak density of about 3.7 × 1010 el/m3 (5.3 × 1010 el/m3) in the retrieved electron-density profile. A planetary boundary layer (−2.35 km~5 km), a troposphere (temperature decreases with height) and a stratosphere (24 km–40 km) clearly appear in the retrieved temperature profile below 50 km. Results show that Tianwen-1 radio occultation data are scientifically reliable and useful for further Mars climate and space-weather studies.

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Section: Mars Atmospheric Profilesmentioning

confidence: 98%

First Observations of Mars Atmosphere and Ionosphere with Tianwen-1 Radio-Occultation Technique on 5 August 2021

Song

et al. 2022

Remote Sensing

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“…Carbon dioxide is the main component, followed by N 2 , O, CO, O 2 , and NO (Nier and McElroy 1977;Nagy and Gregobowsky 2015). Atomic oxygen was never measured until MAVEN arrived at Mars, and was usually obtained via theoretical/numerical modeling.…”

Section: The Vertical Structure Of the Upper Atmosphere Of Marsmentioning

confidence: 99%

Mars: a small terrestrial planet

Mangold

Baratoux

Witasse

et al. 2016

Astron Astrophys Rev

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Mars is characterized by geological landforms familiar to terrestrial geologists. It has a tenuous atmosphere that evolved differently from that of Earth and Venus and a differentiated inner structure. Our knowledge of the structure and evolution of Mars has strongly improved thanks to a huge amount of data of various types (visible and infrared imagery, altimetry, radar, chemistry, etc) acquired by a dozen of missions over the last two decades. In situ data have provided ground truth for remote-sensing data and have opened a new era in the study of Mars geology. While large sections of Mars science have made progress and new topics have emerged, a major question in Mars exploration-the possibility of past or present life-is still unsolved. Without entering into the debate around the presence of life traces, our review develops various topics of Mars science to help the search of life on Mars, building on the most recent discoveries, going from the exosphere to the interior structure, from the magmatic evolution to the currently active processes, including the fate of volatiles and especially liquid water.

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“…The main constituents of Martian atmosphere CO 2 , O, N 2 , CO, O 2 , He and Ar go through a large number of reactions which have both the production and loss rates Nier and McElroy (1977)). Many models have been developed to compute the density profiles of both major and minor neutral and ionic species (Nagy and Grebowsky (2015)). Solar EUV radiation easily penetrates into Martian atmosphere and dissociates CO 2 into CO and O( 3 P ) ground state as shown below (eq.…”

Section: Introductionmentioning

confidence: 99%

The impacts of solar wind on the Martian upper atmosphere

Nagaraja¹,

C.²

2022

Preprint

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Since the first in-situ measurements of the altitude profile of upper atmospheric density and composition were carried out by the Viking lander missions in 1976, similar data are continuously gathered by MAVEN and MOM spacecraft orbiting Mars since their launch in September 2014 with mass spectrometers and other related payloads. Using near-simultaneous observations by the two orbiters, it is seen that both data sets indicate significant day-to-day variations of Argon (Ar) density profiles in the thermosphere-exosphere (∼150-300 km) region during the period 1-15, June 2018, when the solar EUV radiation did not show any appreciable change but the solar wind energetic particle fluxes did so. Extending this study to include the other parent atmospheric constituents (CO 2 , He, N 2 ) and their photochemical products (O, CO) during the same period it is found that the density profiles of CO 2 and O also show similar variations with CO 2 densities showing an increasing trend similar to Ar, but a reversal of this trend for O densities. Using in-situ and near-simultaneous measurements of solar EUV fluxes and the solar wind plasma (e, H + ) velocities and densities near MAVEN periapsis it is noted that unlike the solar EUV radiation (which decreased only by ∼10% between the first and second week of June 2018), solar wind parameters showed a decrease by a factor of 2-3. Hence, it is inferred that the energetic and penetrating solar wind charged particle impact-driven dissociation, ionisation and ion-chemical processes could decrease the CO 2 densities leading to the increase in O densities. This result is also discussed from the considerations of the proton gyro radius effect, pickup ions, sputtering, energetic neutral atoms (ENAs) driven ionisation and ion losses. Further data and modelling efforts would be necessary to confirm this finding.

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Current understanding of the aeronomy of Mars

Cited by 4 publications

References 29 publications

First Observations of Mars Atmosphere and Ionosphere with Tianwen-1 Radio-Occultation Technique on 5 August 2021

First Observations of Mars Atmosphere and Ionosphere with Tianwen-1 Radio-Occultation Technique on 5 August 2021

Mars: a small terrestrial planet

The impacts of solar wind on the Martian upper atmosphere

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