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Short-term variations of Mercury's Na exosphere observed with very high spectral resolution
- Source :
- Geophysical Research Letters. 36
- Publication Year :
- 2009
- Publisher :
- American Geophysical Union (AGU), 2009.
-
Abstract
- [1] Short time variations of Mercury's exosphere cannot be tracked easily from ground based observatories because of the difficulty of distinguishing them from Earth atmospheric effects. On July 13th 2008, using THEMIS solar telescope, we were able to simultaneously measure brightness, Doppler shift and width of the exospheric sodium D2 emission line during half a day with a resolving power of ∼370,000. Mercury's exosphere displayed an emission brightness peak in the Northern hemisphere which vanished in few hours and a more persistent Southern Hemispheric peak. The bulk Doppler shift of the exosphere suggests a period of strong escape from Mercury. The global changes of the Doppler shift and of the Doppler width suggest that a cloud of sodium atoms ejected before or at the beginning of our sequence of observations passed through THEMIS field of view moving anti-sunward. A preferentially southern ejection of sodium atoms leading to the observed persistent southern emission peak is consistent with the orientation of the Interplanetary Magnetic Field during that period.
- Subjects :
- Brightness
010504 meteorology & atmospheric sciences
chemistry.chemical_element
Astrophysics
01 natural sciences
symbols.namesake
0103 physical sciences
Astrophysics::Solar and Stellar Astrophysics
Emission spectrum
Spectral resolution
Interplanetary magnetic field
010303 astronomy & astrophysics
Astrophysics::Galaxy Astrophysics
0105 earth and related environmental sciences
Physics
Northern Hemisphere
Geophysics
Mercury (element)
chemistry
13. Climate action
Physics::Space Physics
symbols
General Earth and Planetary Sciences
Astrophysics::Earth and Planetary Astrophysics
Doppler effect
Exosphere
Subjects
Details
- ISSN :
- 00948276
- Volume :
- 36
- Database :
- OpenAIRE
- Journal :
- Geophysical Research Letters
- Accession number :
- edsair.doi...........ae8825ce87f988144cb3fa9dbebef92c
- Full Text :
- https://doi.org/10.1029/2009gl038089