Volatiles and Refractories in Surface-Bounded Exospheres in the Inner Solar System

Cesare Grava (1) , Rosemary M. Killen (2) , Mehdi Benna (3, 2) , Alexey A. Berezhnoy (4, 5) , Jasper S. Halekas (6) , François Leblanc (7) , Masaki N. Nishino (8) , Christina Plainaki (9) , Jim M. Raines (10) , Menelaos Sarantos (2) , Benjamin D. Teolis (1) , Orenthal J. Tucker (2) , Ronald J. Vervack (11) , Audrey Vorburger (12)

1 SwRI - Southwest Research Institute [San Antonio]
2 GSFC - NASA Goddard Space Flight Center
3 University of Maryland [Baltimore]
4 Sternberg Astronomical Institute [Moscow]
5 IoP - Institute of Physics [Kazan]
6 Department of Physics and Astronomy [Iowa City]
7 HELIOS - LATMOS
8 ISAS - Institute of Space and Astronautical Science
9 Italian Space Agency
10 CLaSP - Department of Climate and Space Sciences and Engineering
11 APL - Johns Hopkins University Applied Physics Laboratory [Laurel, MD]
12 Physikalisches Institut [Bern]

Volatiles and refractories represent the two end-members in the volatility range of species in any surface-bounded exosphere. Volatiles include elements that do not interact strongly with the surface, such as neon (detected on the Moon) and helium (detected both on the Moon and at Mercury), but also argon, a noble gas (detected on the Moon) that surprisingly adsorbs at the cold lunar nighttime surface. Refractories include species such as calcium, magnesium, iron, and aluminum, all of which have very strong bonds with the lunar surface and thus need energetic processes to be ejected into the exosphere. Here we focus on the properties of species that have been detected in the exospheres of inner Solar System bodies, specifically the Moon and Mercury, and how they provide important information to understand source and loss processes of these exospheres, as well as their dependence on variations in external drivers.

Keywords: Moon; Mercury; Exosphere; Refractories; Volatiles; Solar wind; Magnetosphere; Neutrals; Ions

Domains: Astrophysics [astro-ph]

Cesare Grava, Rosemary M. Killen, Mehdi Benna, Alexey A. Berezhnoy, Jasper S. Halekas, et al.. Volatiles and Refractories in Surface-Bounded Exospheres in the Inner Solar System. Space Science Reviews, 2021, 217, pp.61. ⟨10.1007/s11214-021-00833-8⟩. ⟨insu-03263459⟩