Revised element abundances for WC-type central stars
Abstract
According to previous spectral analyses of Wolf-Rayet type central stars, late [WC] subtypes show systematically higher carbon-to-helium abundance ratios than early [WC] subtypes. If this were true, it would rule out that these stars form an evolutionary sequence. However, due to the different parameter domains and diagnostic lines, one might suspect systematic errors being the source of this discrepancy. In an ongoing project we are therefore checking the [WC] analyses by means of the last generation of non-LTE models for expanding stellar atmospheres which account for line-blanketing and wind clumping. So far, the abundance discrepancy is not resolved. Further element abundances (H, N, Fe) are determined and compared with evolutionary predictions.
Cite
@article{arxiv.0712.3480,
title = {Revised element abundances for WC-type central stars},
author = {H. Todt and G. Gräfener and W. -R. Hamann},
journal= {arXiv preprint arXiv:0712.3480},
year = {2009}
}
Comments
4 pages, 5 figures, in conference proceedings of "Planetary Nebulae in our Galaxy and Beyond" IAU Symposion 234, 2006, editors: Michael J. Barlow, Roberto H. M\'endez