title: Mercury's complex exosphere: results from MESSENGER's third flyby.
abstract: During MESSENGER's third flyby of Mercury, the Mercury Atmospheric and Surface Composition Spectrometer detected emission from ionized calcium concentrated 1 to 2 Mercury radii tailward of the planet. This measurement provides evidence for tailward magnetospheric convection of photoions produced inside the magnetosphere. Observations of neutral sodium, calcium, and magnesium above the planet's north and south poles reveal altitude distributions that are distinct for each species. A two-component sodium distribution and markedly different magnesium distributions above the two poles are direct indications that multiple processes control the distribution of even single species in Mercury's exosphere.
authors.affiliation: Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA. Ron.Vervack@jhuapl.edu
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Vervack
authors.forename: William E
authors.initials: WE
authors.lastname: McClintock
authors.forename: Rosemary M
authors.initials: RM
authors.lastname: Killen
authors.forename: Ann L
authors.initials: AL
authors.lastname: Sprague
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Anderson
authors.forename: Matthew H
authors.initials: MH
authors.lastname: Burger
authors.forename: E Todd
authors.initials: ET
authors.lastname: Bradley
authors.forename: Nelly
authors.initials: N
authors.lastname: Mouawad
authors.forename: Sean C
authors.initials: SC
authors.lastname: Solomon
authors.forename: Noam R
authors.initials: NR
authors.lastname: Izenberg