Title

Observations Of Metallic Species In Mercury'S Exosphere

Keywords

Mercury, Atmosphere; Mercury, Surface

Abstract

From observations of the metallic species sodium (Na), potassium (K), and magnesium (Mg) in Mercury's exosphere, we derive implications for source and loss processes. All metallic species observed exhibit a distribution and/or line width characteristic of high to extreme temperature - tens of thousands of degrees K. The temperatures of refractory species, including magnesium and calcium, indicate that the source process for the atoms observed in the tail and near-planet exosphere are consistent with ion sputtering and/or impact vaporization of a molecule with subsequent dissociation into the atomic form. The extended Mg tail is consistent with a surface abundance of 5-8% Mg by number, if 30% of impact-vaporized Mg remains as MgO and half of the impact vapor condenses. Globally, ion sputtering is not a major source of Mg, but locally the sputtered source can be larger than the impact vapor source. We conclude that the Na and K in Mercury's exosphere can be derived from a regolith composition similar to that of Luna 16 soil (or Apollo 17 orange glass), in which the abundance by number is 0.0027 (0.0028) for Na and 0.0006 (0.0045) for K. © 2010.

Publication Date

9-1-2010

Publication Title

Icarus

Volume

209

Issue

1

Number of Pages

75-87

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1016/j.icarus.2010.02.018

Socpus ID

77955770567 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/77955770567

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