title: Mercury's exosphere: observations during MESSENGER's First Mercury flyby.
abstract: During MESSENGER's first Mercury flyby, the Mercury Atmospheric and Surface Composition Spectrometer measured Mercury's exospheric emissions, including those from the antisunward sodium tail, calcium and sodium close to the planet, and hydrogen at high altitudes on the dayside. Spatial variations indicate that multiple source and loss processes generate and maintain the exosphere. Energetic processes connected to the solar wind and magnetospheric interaction with the planet likely played an important role in determining the distributions of exospheric species during the flyby.
authors.affiliation: Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80303, USA. william.mcclintock@lasp.colorado.edu
authors.forename: William E
authors.initials: WE
authors.lastname: McClintock
authors.forename: E Todd
authors.initials: ET
authors.lastname: Bradley
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Vervack
authors.forename: Rosemary M
authors.initials: RM
authors.lastname: Killen
authors.forename: Ann L
authors.initials: AL
authors.lastname: Sprague
authors.forename: Noam R
authors.initials: NR
authors.lastname: Izenberg
authors.forename: Sean C
authors.initials: SC
authors.lastname: Solomon