Mars’ ultraviolet dayglow observations by IUVS/MAVEN: Structure and variability of Martian upper atmosphere
| Autor: | Jain, Sonal K., Stewart, Ian, Schneider, Nicholas M., Deighan, Justin, Stiepen, Arnaud, Evans, Joseph, Stevens, Michael H., Chaffin, Michael S., Crismani, Matteo, Mcclintock, Bill, Clarke, John, Holsclaw, Greg, Lo, Daniel, Lefèvre, Franck, Montmessin, Franck, Thiemann, Ed, Epavier, Francis, Jakosky, Bruce M. |
|---|---|
| Přispěvatelé: | Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Computational Physics, Inc., Naval Research Laboratory (NRL), Center for Space Physics [Boston] (CSP), Boston University [Boston] (BU), University of Arizona, STRATO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Cardon, Catherine |
| Jazyk: | angličtina |
| Rok vydání: | 2015 |
| Předmět: |
[SDU.ASTR.IM] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM]
[SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR] [SDU.ASTR.SR] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR] [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP] [SDU.ASTR.EP] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP] [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM] |
| Zdroj: | AGU Fall Meeting 2015 AGU Fall Meeting 2015, Dec 2015, San Francisco, United States. pp.P21A-2058 |
| Popis: | International audience; Mars has been studied extensively at ultraviolet wavelengths starting from Mariner 6 and 7 (Barth et al. JGR, 1971; Stewart, JGR, 1972), Mariner 9 (Barth et al., Icaurs, 1972; Stewart et al. Icarus, 1972), and more recently by SPICAM aboard Mars Express (Leblanc et al., JGR, 2006). The results from these measurements reveal a large variability in the composition and structure of Martian upper atmosphere. However, due to the lack of simultaneous measurements of energy input in the atmosphere, such as solar electromagnetic and particle flux as well as limitations in the observation geometry and data itself, this variability is still not fully understood.We report a comprehensive study of Mars dayglow observations by the Imaging Ultraviolet Spectrograph (IUVS) aboard the Mars Atmosphere and Volatile EvolutioN (MAVEN) satellite, focusing on upper atmospheric structure and seasonal variability. The dayglow emission spectra show features similar to previous UV measurements at Mars. The IUVS detected a second, low-altitude peak in the emission profile of OI 297.2 nm, confirmation of the prediction that the absorption of solar Lyman alpha emission is an important energy source there. We find a significant drop in thermospheric scale height and temperature between Ls = 218° and Ls = 337 - 352°, attributed primarily to the decrease in solar activity and increase in heliocentric distance. The CO2+ UVD peak intensity is well correlated with simultaneous observations of solar 17 - 22 nm irradiance at Mars by Extreme Ultraviolet Monitor (EUVM) aboard MAVEN. I will present and discuss the variability in Martian UV dayglow, its dependence on solar EUV irradiance, and the importance of IUVS observations in our current understanding of Mars’ thermosphere. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|