Title

Observations of metallic species in Mercury's exosphere

Authors

Authors

R. M. Killen; A. E. Potter; R. J. Vervack; E. T. Bradley; W. E. McClintock; C. M. Anderson;M. H. Burger

Comments

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Abbreviated Journal Title

Icarus

Keywords

Mercury, Atmosphere; Mercury, Surface; STIMULATED DESORPTION; ATMOSPHERE; POTASSIUM; SODIUM; IONS; MOON; DISCOVERY; SURFACE; IMPACT; NA; Astronomy & Astrophysics

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 tall 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 (C) Published by Elsevier Inc

Journal Title

Icarus

Volume

209

Issue/Number

1

Publication Date

1-1-2010

Document Type

Article

Language

English

First Page

75

Last Page

87

WOS Identifier

WOS:000281687800009

ISSN

0019-1035

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