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The lunar neon exosphere seen in LACE data.

Authors :
Killen, Rosemary M.
Williams, David R.
Park, Jaekyun
Tucker, Orenthal J.
Kim, Sang-Joon
Source :
ICARUS. Sep2019, Vol. 329, p246-250. 5p.
Publication Year :
2019

Abstract

Using the LACE data from Apollo 17 we have found measured neon densities consistent with the 20Ne surface number densities reported by Cook et al. (2013) for normal conditions, terminator surface densities of 3 (±1.5) × 103 cm−3. These values are almost an order of magnitude less than those reported by Benna et al. (2015) for CME conditions. Using a Monte Carlo model and assuming the normal solar wind and a photoionization lifetime for Ne of 300 days, our result was more consistent with the Benna (2015) result than our measured result. Two lunations showed an increase in Ne during the night, consistent with the simulation, but two of the lunations showed a decrease in surface number density through the night. We have shown that explaining the Ne distribution is not as simple as assuming dynamic equilibrium with the solar wind and an exosphere accommodated to the local surface temperature. • LACE data from Apollo 17 have been reanalyzed. • The 20Ne nightside surface number densities are 3 (±1.5) × 103 cm−3. • Ne cannot be modeled assuming dynamic equilibrium with the solar wind. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00191035
Volume :
329
Database :
Academic Search Index
Journal :
ICARUS
Publication Type :
Academic Journal
Accession number :
136498849
Full Text :
https://doi.org/10.1016/j.icarus.2019.04.018