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A&A 443, 293-296 (2005)
DOI: 10.1051/0004-6361:20053412
Non-LTE modelling of the He I 10830 Å line in early-type main sequence stars
N. PrzybillaDr. Remeis-Sternwarte Bamberg, Universität Erlangen-Nürnberg, Sternwartstrasse 7, 96049 Bamberg, Germany
e-mail: przybilla@sternwarte.uni-erlangen.de
(Received 12 May 2005 / Accepted 3 July 2005)
Abstract
The near-IR
10 830 Å transition is a highly sensitive diagnostic for
non-LTE effects in astrophysical plasmas. So far, non-LTE line-formation
computations have failed to quantitatively reproduce observations of this line
in the entire range of early-A to late-O main sequence stars.
It is shown that the non-LTE modelling
was insufficient, for the most part, either because of
inaccurate photoionization cross-sections for the 2s 3S state or
because of neglecting line blocking.
New calculations based on state-of-the-art atomic data give excellent
agreement with observation for the
10 830 Å feature, while
profiles of the
lines in the visual are retained.
Key words: line: formation -- infrared: stars -- stars: early-type
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