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1. Martian Thermospheric Response to an X8.2 Solar Flare on 10 September 2017 as Seen by MAVEN/IUVS

Author

Jain, S. K., primary, Deighan, J., additional, Schneider, N. M., additional, Stewart, A. I. F., additional, Evans, J. S., additional, Thiemann, E. M. B., additional, Chaffin, M. S., additional, Crismani, M., additional, Stevens, M. H., additional, Elrod, M. K., additional, Stiepen, A., additional, McClintock, W. E., additional, Lo, D. Y., additional, Clarke, J. T., additional, Eparvier, F. G., additional, Lefévre, F., additional, Montmessin, F., additional, Holsclaw, G. M., additional, Chamberlin, P. C., additional, and Jakosky, B. M., additional

Published
2018
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2. Global Aurora on Mars During the September 2017 Space Weather Event

Author

Schneider, N. M., primary, Jain, S. K., additional, Deighan, J., additional, Nasr, C. R., additional, Brain, D. A., additional, Larson, D., additional, Lillis, R., additional, Rahmati, Ali, additional, Halekas, J. S., additional, Lee, C. O., additional, Chaffin, M. S., additional, Stiepen, A., additional, Crismani, M., additional, Evans, J. S., additional, Stevens, M. H., additional, Lo, D. Y., additional, McClintock, W. E., additional, Stewart, A. I. F., additional, Yelle, R. V., additional, Clarke, J. T., additional, Holsclaw, G. M., additional, Lefevre, F., additional, Montmessin, F., additional, and Jakosky, B. M., additional

Published
2018
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3. Martian mesospheric cloud observations by IUVS on MAVEN: Thermal tides coupled to the upper atmosphere

Author

Stevens, M. H., primary, Siskind, D. E., additional, Evans, J. S., additional, Jain, S. K., additional, Schneider, N. M., additional, Deighan, J., additional, Stewart, A. I. F., additional, Crismani, M., additional, Stiepen, A., additional, Chaffin, M. S., additional, McClintock, W. E., additional, Holsclaw, G. M., additional, Lefèvre, F., additional, Lo, D. Y., additional, Clarke, J. T., additional, Montmessin, F., additional, and Jakosky, B. M., additional

Published
2017
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5. Global classification of MESSENGER spectral reflectance data and lab spectra comparison

Author

D'Amore, Mario, Helbert, Jörn, Maturilli, Alessandro, Head, J.W., Sprague, A. L., Izenberg, N. R., Holsclaw, G. M., McClintock, W. E., Vilas, F., and Solomon, S.C.

Subjects
MESSENGER Mercury, Experimentelle Planetenphysik
Abstract

The MESSENGER spacecraft continues to provide new data that change our views on the nature of Mercury’s surface. Assuming that surface composition can be derived from spectral reflectance measurements with the use of statistical techniques, we have employed unsupervised hierarchical clustering analyses to identify spectral units from MESSENGER’s Mercury Atmospheric and Surface Composition Spectrometer (MASCS) observations. To retrieve the number and spectral shapes of the different components present in the dataset, we collected all MASCS observations to date (> 1.5 milion spectra). Because there are no photometric corrections for MASCS available yet, the data were normalized to the reflectance level at 700 nm, yielding a ratio nearly independent of incidence and emission angles. Independent tests on laboratory data show that this approach is effective in reducing phase angle variations. The data were then interpolated to a fixed spatial grid, averaging the sub-pixel spectra. The product is a map of reflectance ratio, along with error and frequency maps to address potential error in the process and to assess reliability. This is the first global geographically registered cube-image of averaged MASCS spectra. We produced a spatial grid resolution between 4 pixels per degree (ppd) for global analyses and 0.5 ppd for regional studies. The unsupervised hierarchical clustering of the global MASCS cube-image produces a tree of data partition, starting from two mega-regions. The first mega-region (MR1) comprises equatorial to mid-latitudes and the second (MR2) the two poles. The boundaries of MR2 at high northern latitudes approximate those of the volcanic northern plains. MR2 areas show redder MASCS spectra than do MR1 areas. The spectral units show some correlation with surface units mapped by visible image acquired by MESSENGER and documented the presence of distinct spectral units on Mercury, as characterized by MASCS observations.Moreover, it seems to closely match some Gamma Ray Spectrometer elemental abudances results and global distribution of pyroclastic geological features. Following iteration produces finer separation of the surface in smaller regions. Each region average spectra is compared with reflectance spectra collected at the Berlin PEL laboratory. Here the angular dependency is treated as in the MASCS data, via normalization at 700nm. This allow us to start a geological and geochemical interpretations of MASCS observations. The materials selected aim to explore the analogs for Hollow-Forming Material on Mercury theory in : a komatiitic substrate with superimposed sulfides layer, due flotation in melted lava during volcanic eruption. We used komatiite spectra from PEL sample collection and various Mg-, Ca- and Mn- bearing sulfides. both at low and high temperature to explore the thermal schok effect on sulfide volatilization and on komatiitic substrate.

Published
2012

6. Probing the Martian atmosphere with MAVEN/IUVS stellar occultations

Author

Gröller, H., primary, Yelle, R. V., additional, Koskinen, T. T., additional, Montmessin, F., additional, Lacombe, G., additional, Schneider, N. M., additional, Deighan, J., additional, Stewart, A. I. F., additional, Jain, S. K., additional, Chaffin, M. S., additional, Crismani, M. M. J., additional, Stiepen, A., additional, Lefèvre, F., additional, McClintock, W. E., additional, Clarke, J. T., additional, Holsclaw, G. M., additional, Mahaffy, P. R., additional, Bougher, S. W., additional, and Jakosky, B. M., additional

Published
2015
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7. The structure and variability of Mars upper atmosphere as seen in MAVEN/IUVS dayglow observations

Author

Jain, S. K., primary, Stewart, A. I. F., additional, Schneider, N. M., additional, Deighan, J., additional, Stiepen, A., additional, Evans, J. S., additional, Stevens, M. H., additional, Chaffin, M. S., additional, Crismani, M., additional, McClintock, W. E., additional, Clarke, J. T., additional, Holsclaw, G. M., additional, Lo, D. Y., additional, Lefèvre, F., additional, Montmessin, F., additional, Thiemann, E. M. B., additional, Eparvier, F., additional, and Jakosky, B. M., additional

Published
2015
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8. Retrieval of CO2 and N2 in the Martian thermosphere using dayglow observations by IUVS on MAVEN

Author

Evans, J. S., primary, Stevens, M. H., additional, Lumpe, J. D., additional, Schneider, N. M., additional, Stewart, A. I. F., additional, Deighan, J., additional, Jain, S. K., additional, Chaffin, M. S., additional, Crismani, M., additional, Stiepen, A., additional, McClintock, W. E., additional, Holsclaw, G. M., additional, Lefèvre, F., additional, Lo, D. Y., additional, Clarke, J. T., additional, Eparvier, F. G., additional, Thiemann, E. M. B., additional, Chamberlin, P. C., additional, Bougher, S. W., additional, Bell, J. M., additional, and Jakosky, B. M., additional

Published
2015
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9. Three‐dimensional structure in the Mars H corona revealed by IUVS on MAVEN

Author

Chaffin, M. S., primary, Chaufray, J. Y., additional, Deighan, J., additional, Schneider, N. M., additional, McClintock, W. E., additional, Stewart, A. I. F., additional, Thiemann, E., additional, Clarke, J. T., additional, Holsclaw, G. M., additional, Jain, S. K., additional, Crismani, M. M. J., additional, Stiepen, A., additional, Montmessin, F., additional, Eparvier, F. G., additional, Chamberlain, P. C., additional, and Jakosky, B. M., additional

Published
2015
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10. Study of the Martian cold oxygen corona from the O I 130.4 nm by IUVS/MAVEN

Author

Chaufray, J. Y., primary, Deighan, J., additional, Chaffin, M. S., additional, Schneider, N. M., additional, McClintock, W. E., additional, Stewart, A. I. F., additional, Jain, S. K., additional, Crismani, M., additional, Stiepen, A., additional, Holsclaw, G. M., additional, Clarke, J. T., additional, Montmessin, F., additional, Eparvier, F. G., additional, Thiemann, E. M. B., additional, Chamberlin, P. C., additional, and Jakosky, B. M., additional

Published
2015
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11. New observations of molecular nitrogen in the Martian upper atmosphere by IUVS on MAVEN

Author

Stevens, M. H., primary, Evans, J. S., additional, Schneider, N. M., additional, Stewart, A. I. F., additional, Deighan, J., additional, Jain, S. K., additional, Crismani, M., additional, Stiepen, A., additional, Chaffin, M. S., additional, McClintock, W. E., additional, Holsclaw, G. M., additional, Lefèvre, F., additional, Lo, D. Y., additional, Clarke, J. T., additional, Montmessin, F., additional, Bougher, S. W., additional, and Jakosky, B. M., additional

Published
2015
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12. MAVEN IUVS observation of the hot oxygen corona at Mars

Author

Deighan, J., primary, Chaffin, M. S., additional, Chaufray, J.‐Y., additional, Stewart, A. I. F., additional, Schneider, N. M., additional, Jain, S. K., additional, Stiepen, A., additional, Crismani, M., additional, McClintock, W. E., additional, Clarke, J. T., additional, Holsclaw, G. M., additional, Montmessin, F., additional, Eparvier, F. G., additional, Thiemann, E. M. B., additional, Chamberlin, P. C., additional, and Jakosky, B. M., additional

Published
2015
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13. MAVEN IUVS observations of the aftermath of the Comet Siding Spring meteor shower on Mars

Author

Schneider, N. M., primary, Deighan, J. I., additional, Stewart, A. I. F., additional, McClintock, W. E., additional, Jain, S. K., additional, Chaffin, M. S., additional, Stiepen, A., additional, Crismani, M., additional, Plane, J. M. C., additional, Carrillo‐Sánchez, J. D., additional, Evans, J. S., additional, Stevens, M. H., additional, Yelle, R. V., additional, Clarke, J. T., additional, Holsclaw, G. M., additional, Montmessin, F., additional, and Jakosky, B. M., additional

Published
2015
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16. Retrieval of CO2and N2in the Martian thermosphere using dayglow observations by IUVS on MAVEN

Author

Evans, J. S., Stevens, M. H., Lumpe, J. D., Schneider, N. M., Stewart, A. I. F., Deighan, J., Jain, S. K., Chaffin, M. S., Crismani, M., Stiepen, A., McClintock, W. E., Holsclaw, G. M., Lefèvre, F., Lo, D. Y., Clarke, J. T., Eparvier, F. G., Thiemann, E. M. B., Chamberlin, P. C., Bougher, S. W., Bell, J. M., and Jakosky, B. M.

Abstract

We present direct number density retrievals of carbon dioxide (CO2) and molecular nitrogen (N2) for the upper atmosphere of Mars using limb scan observations during October and November 2014 by the Imaging Ultraviolet Spectrograph on board NASA's Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft. We use retrieved CO2densities to derive temperature variability between 170 and 220 km. Analysis of the data shows (1) low‐mid latitude northern hemisphere CO2densities at 170 km vary by a factor of about 2.5, (2) on average, the N2/CO2increases from 0.042 ± 0.017 at 130 km to 0.12 ± 0.06 at 200 km, and (3) the mean upper atmospheric temperature is 324 ± 22 K for local times near 14:00. Retrieved CO2densities at 170 km vary by a factor of about 2.5On average, N2/CO2increases from 4% at 130 km to 12% at 200 kmMean Martian upper atmospheric temperature over the sampled time frame is 324 {±} 22 K

Published
2015
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17. Martian water loss to space enhanced by regional dust storms

Author

Chaffin, M. S., Kass, D. M., Aoki, S., Fedorova, A. A., Deighan, J., Connour, K., Heavens, N. G., Kleinböhl, A., Jain, S. K., Chaufray, J.-Y., Mayyasi, M., Clarke, J. T., Stewart, A. I. F., Evans, J. S., Stevens, M. H., McClintock, W. E., Crismani, M. M. J., Holsclaw, G. M., Lefevre, F., Lo, D. Y., Montmessin, F., Schneider, N. M., Jakosky, B., Villanueva, G., Liuzzi, G., Daerden, F., Thomas, I. R., Lopez-Moreno, J.-J., Patel, M.R., Bellucci, G., Ristic, B., Erwin, J. T., Vandaele, A. C., Trokhimovskiy, A., Korablev, O. I., Chaffin, M. S., Kass, D. M., Aoki, S., Fedorova, A. A., Deighan, J., Connour, K., Heavens, N. G., Kleinböhl, A., Jain, S. K., Chaufray, J.-Y., Mayyasi, M., Clarke, J. T., Stewart, A. I. F., Evans, J. S., Stevens, M. H., McClintock, W. E., Crismani, M. M. J., Holsclaw, G. M., Lefevre, F., Lo, D. Y., Montmessin, F., Schneider, N. M., Jakosky, B., Villanueva, G., Liuzzi, G., Daerden, F., Thomas, I. R., Lopez-Moreno, J.-J., Patel, M.R., Bellucci, G., Ristic, B., Erwin, J. T., Vandaele, A. C., Trokhimovskiy, A., and Korablev, O. I.

Abstract

Mars has lost most of its initial water to space as atomic hydrogen and oxygen. Spacecraft measurements have determined that present-day hydrogen escape undergoes large variations with season that are inconsistent with long-standing explanations. The cause is incompletely understood, with likely contributions from seasonal changes in atmospheric circulation, dust activity and solar extreme ultraviolet input. Although some modelling and indirect observational evidence suggest that dust activity can explain the seasonal trend, no previous study has been able to unambiguously distinguish seasonal from dust-driven forcing. Here we present synoptic measurements of dust, temperature, ice, water and hydrogen on Mars during a regional dust event, demonstrating that individual dust events can boost planetary H loss by a factor of five to ten. This regional storm occurred in the declining phase of the known seasonal trend, establishing that dust forcing can override this trend to drive enhanced escape. Because similar regional storms occur in most Mars years, these storms may be responsible for a large fraction of Martian water loss and represent an important driver of Mars atmospheric evolution.

18. Martian water loss to space enhanced by regional dust storms

Author

Chaffin, M. S., Kass, D. M., Aoki, S., Fedorova, A. A., Deighan, J., Connour, K., Heavens, N. G., Kleinböhl, A., Jain, S. K., Chaufray, J.-Y., Mayyasi, M., Clarke, J. T., Stewart, A. I. F., Evans, J. S., Stevens, M. H., McClintock, W. E., Crismani, M. M. J., Holsclaw, G. M., Lefevre, F., Lo, D. Y., Montmessin, F., Schneider, N. M., Jakosky, B., Villanueva, G., Liuzzi, G., Daerden, F., Thomas, I. R., Lopez-Moreno, J.-J., Patel, M.R., Bellucci, G., Ristic, B., Erwin, J. T., Vandaele, A. C., Trokhimovskiy, A., Korablev, O. I., Chaffin, M. S., Kass, D. M., Aoki, S., Fedorova, A. A., Deighan, J., Connour, K., Heavens, N. G., Kleinböhl, A., Jain, S. K., Chaufray, J.-Y., Mayyasi, M., Clarke, J. T., Stewart, A. I. F., Evans, J. S., Stevens, M. H., McClintock, W. E., Crismani, M. M. J., Holsclaw, G. M., Lefevre, F., Lo, D. Y., Montmessin, F., Schneider, N. M., Jakosky, B., Villanueva, G., Liuzzi, G., Daerden, F., Thomas, I. R., Lopez-Moreno, J.-J., Patel, M.R., Bellucci, G., Ristic, B., Erwin, J. T., Vandaele, A. C., Trokhimovskiy, A., and Korablev, O. I.

Abstract

Mars has lost most of its initial water to space as atomic hydrogen and oxygen. Spacecraft measurements have determined that present-day hydrogen escape undergoes large variations with season that are inconsistent with long-standing explanations. The cause is incompletely understood, with likely contributions from seasonal changes in atmospheric circulation, dust activity and solar extreme ultraviolet input. Although some modelling and indirect observational evidence suggest that dust activity can explain the seasonal trend, no previous study has been able to unambiguously distinguish seasonal from dust-driven forcing. Here we present synoptic measurements of dust, temperature, ice, water and hydrogen on Mars during a regional dust event, demonstrating that individual dust events can boost planetary H loss by a factor of five to ten. This regional storm occurred in the declining phase of the known seasonal trend, establishing that dust forcing can override this trend to drive enhanced escape. Because similar regional storms occur in most Mars years, these storms may be responsible for a large fraction of Martian water loss and represent an important driver of Mars atmospheric evolution.

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