Abundances and radial velocity analysis of BW Vulpeculae^*

¹ SCI-SA, Research and Scientific Support Department of ESA, ESTEC, 2200 AG Noordwijk, The Netherlands e-mail: Malcolm.Fridlund@esa.int
² Astronomy Division, PO Box 3000, 90014 University of Oulu, Finland e-mail: ilya.ilyin@oulu.fi

Corresponding author: A. Stankov, Anamarija.Stankov@esa.int

Received: 12 March 2003
Accepted: 10 June 2003

Abstract

We present the results of the analysis of 56 échelle spectra of the β Cephei star BW Vulpeculae. The data were obtained during three nights with the SOFIN spectrograph at the Nordic Optical Telescope and cover a wavelength range from 3650 Å to 7340 Å. We compare the observed spectrum with a synthetic spectrum calculated from a model atmosphere for this star utilizing the program ATLAS9 by Kurucz. From this, we determine a projected rotational velocity, , of 24 km s^-1. 
Detailed spectral line identification and an abundance analysis for this star are performed. From these analyses we find that Ne, Si, He, and Ar are over-abundant in BW Vulpeculae, while the abundances for N, S, O, Fe, C, and Al are solar. 
Finally, a comparison of radial velocity curves from six different layers of BW Vulpeculae's atmosphere is presented, corresponding to the formation depths of different elements. We show that at least six of these layers move independently from each other.