MESSENGER observations of Mercury's exosphere: detection of magnesium and distribution of constituents.

摘要: Mercury is surrounded by a tenuous exosphere that supplied primarily the planet's surface materials and known to contain sodium, potassium, calcium. Observations Atmospheric Surface Composition Spectrometer during MESSENGER's second flyby revealed presence of neutral magnesium in tail (anti-sunward) region exosphere, as well differing spatial distributions magnesium, calcium, sodium atoms both nightside, near-planet exosphere. Analysis these observations, supplemented observations first flyby, those other MESSENGER instruments, suggests distinct arise from combination differences source, transfer, loss processes.