Towards an understanding of the Ofp star HD 191612: optical spectroscopy - AstrophysicsReport as inadecuate




Towards an understanding of the Ofp star HD 191612: optical spectroscopy - Astrophysics - Download this document for free, or read online. Document in PDF available to download.

Abstract: We present extensive optical spectroscopy of the early-type magnetic star HD191612 O6.5f?pe-O8fp. The Balmer and HeI lines show strongly variableemission which is highly reproducible on a well-determined 538-d period. Metallines and HeII absorptions including many selective emission lines butexcluding He II 4686A emission are essentially constant in line strength, butare variable in velocity, establishing a double-lined binary orbit with Porb= 1542d, e=0.45. We conduct a model-atmosphere analysis of the primary, andfind that the system is consistent with a O8: giant with a B1: main-sequencesecondary. Since the periodic 538-d changes are unrelated to orbital motion,rotational modulation of a magnetically constrained plasma is strongly favouredas the most likely underlying `clock-. An upper limit on the equatorialrotation is consistent with this hypothesis, but is too weak to provide astrong constraint.



Author: Ian D. Howarth, Nolan R. Walborn, Danny J. Lennon, Joachim Puls, Yael Naze, K. Annuk, I. Antokhin, D. Bohlender, H. Bond, J.-F. D

Source: https://arxiv.org/







Related documents