Solar Wind Charge Exchange X-rays
from unmagnetised planets
The solar wind contains a small fraction of highly charge ions such as
O
6+, C
6+, and Ne
8+. When the solar
wind meets the neutral exosphere of a planet, some of these ions will
undergo charge exchange collisions with the exospheric neutrals. These
collisions will leave ions in highly excited states, and when the ions
return to the ground state photons in the soft X-ray range are emitted.
The Solar Wind Charge Exchange process is responsible for the X-ray
halo that has been observed around Mars (Dennerl, et al.,
Astronomy & Astrophysics, vol. 451, 709-722, 2006,
doi:10.1051/0004-6361:20054253;
Gunell, et al., Geophysical Research Letters, vol. 31, L22801, 2004
,
doi:10.1029/2004GL020953).
Solar Wind Charge Exchange X-rays also exist at Venus
(Gunell et al., Geophysical Research Letters, vol. 34, L03107, 2007,
doi:10.1029/2006GL028602).
A simulated X-ray image of Mars.
Related publications
- "X-rays
from Solar Wind Charge Exchange at Mars: A Comparison of Simulations
and Observations" by H. Gunell, M. Holmström, E. Kallio, P.
Janhunen, and K. Dennerl,
An edited version of this paper was published by AGU. Copyright 2004
American Geophysical Union,
Geophysical Research Letters, vol. 31, L22801, doi:10.1029/2004GL020953,
2004.
- "Simulations
of X-rays from SolarWind Charge Exchange at Mars: Parameter dependence"
by H. Gunell, M. Holmström, E. Kallio, P. Janhunen, and K.
Dennerl,
Advances in Space Research, vol. 36, 2057-2065,
doi:10.1016/j.asr.2005.06.007, 2005.
- "First observation of Mars with XMM-Newton:
High resolution X-ray spectroscopy with RGS"
by K. Dennerl, C. M. Lisse, A. Bhardwaj, V. Burwitz, J. Englhauser,
H. Gunell, M. Holmström, F. Jansen, V. Kharchenko,
and P. M. Rodriguez-Pascual,
Astronomy & Astrophysics, vol. 451, 709-722,
doi: 10.1051/0004-6361:20054253, 2006.
- "Simulations
of Solar Wind Charge Exchange X-ray emissions at Venus" by H. Gunell,
E. Kallio, R. Jarvinen, P. Janhunen, M. Holmström, and K. Dennerl,
An edited version of this paper was published by AGU. Copyright 2006
American Geophysical Union,
Geophysical Research Letters, vol. 34, L03107, doi:10.1029/2006GL028602,
2007.
Updated 2008-07-03
