Iron abundances from optical Fe III absorption lines in B-type stellar spectra
Abstract
The role of optical Fe III absorption lines in B-type stars as iron abundance diagnostics is considered. To date, ultraviolet Fe lines have been widely used in B-type stars, although line blending can severely hinder their diagnostic power. Using optical spectra, covering a wavelength range ~ 3560 - 9200 A, a sample of Galactic B-type main-sequence and supergiant stars of spectral types B0.5 to B7 are investigated. A comparison of the observed Fe III spectra of supergiants, and those predicted from the model atmosphere codes TLUSTY (plane-parallel, non-LTE), with spectra generated using SYNSPEC (LTE), and CMFGEN (spherical, non-LTE), reveal that non-LTE effects appear small. In addition, a sample of main-sequence and supergiant objects, observed with FEROS, reveal LTE abundance estimates consistent with the Galactic environment and previous optical studies. Based on the present study, we list a number of Fe III transitions which we recommend for estimating the iron abundance from early B-type stellar spectra.
Cite
@article{arxiv.0710.3252,
title = {Iron abundances from optical Fe III absorption lines in B-type stellar spectra},
author = {H. M. A. Thompson and F. P. Keenan and P. L. Dufton and C. Trundle and R. S. I. Ryans and P. A. Crowther},
journal= {arXiv preprint arXiv:0710.3252},
year = {2009}
}
Comments
3 figures and 8 tables. Table 3 is to be published online only (included here on last page). Accepted for publication in MNRAS