Mercury's Exosphere During MESSENGER's Second Flyby: Detection of Magnesium and Distinct Distributions of Neutral Species

摘要: During MESSENGER's second Mercury flyby, the Atmospheric and Surface Composition Spectrometer observed emission from Mercury's neutral exosphere. These observations include first detection of magnesium. Differing spatial distributions for sodium, calcium, magnesium were revealed by beginning in tail region, approximately 8 radii anti-sunward planet, continuing past nightside, ending near dawn terminator. Analysis these observations, supplemented during flyby as well those other MESSENGER instruments, suggests that distinct arise a combination differences source, transfer, loss processes.