Astronomy & Astrophysics

Free access article

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. Przybilla

Dr. 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 $\ion{i}$ 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 $\ion{i}$ 10 830 Å feature, while profiles of the $\ion{i}$ lines in the visual are retained.

Key words: line: formation -- infrared: stars -- stars: early-type

SIMBAD Objects

What is OpenURL?