| Issue |
A&A
Volume 552, April 2013
|
|
|---|---|---|
| Article Number | A33 | |
| Number of page(s) | 3 | |
| Section | Astrophysical processes | |
| DOI | https://doi.org/10.1051/0004-6361/201220699 | |
| Published online | 20 March 2013 | |
Research Note
Excitation and deexcitation processes in atom-Rydberg atom collisions in helium-rich white dwarf atmospheres
1
University of Belgrade, Institute of physics,
PO Box 57,
11001
Belgrade,
Serbia
e-mail:
vlada@ipb.ac.rs
2
Institute Isaac Newton of Chile, Yugoslavia Branch, 11060
Belgrade,
Serbia
3
Astronomical Observatory, Volgina 7, 11060
Belgrade 74, Serbia
4
Observatoire de Paris, 92195
Meudon Cedex,
France
Received:
6
November
2012
Accepted:
14
February
2013
We aim to show the importance of non-elastic excitation and deexcitation processes in He∗(n) + He(1s2) collisions with the principal quantum number n ≥ 3 for helium-rich white dwarf atmospheres. We compare the efficiencies of these processes with those of the known non-elastic electron-He∗(n) atom processes in the atmospheres of some DB white dwarfs. We show that in significant parts of the considered atmospheres, which contain weakly ionized layers (the ionization degree ≲10-3), the influence of the studied atom-Rydberg atom processes on excited helium atom populations is dominant or at least comparable to the influence of the concurrent electron-He∗(n)-atom processes.
Key words: atomic processes / astrochemistry / stars: atmospheres / white dwarfs
© ESO, 2013
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