Rotational velocities of A-type stars - I. Measurement of in the southern hemisphere (original) (raw)

A&A 381, 105-121 (2002)

I. Measurement of $v\sin i$ in the southern hemisphere

1 Observatoire de Genève, 51 chemin des Maillettes, 1290 Sauverny, Switzerland
2 DASGAL/CNRS UMR 8633, Observatoire de Paris, 5 place Janssen, 92195 Meudon Cedex, France
3 CNRS, Institut d'Astrophysique de Paris, 98bis boulevard Arago, 75014 Paris, France
4 Université de Paris-Sud XI, 91405 Orsay Cedex, France
5 Dipartimento di Astronomia, Università degli Studi di Trieste, via Tiepolo 11, 34131 Trieste, Italy

Corresponding author: F. Royer, frederic.royer@obs.unige.ch

Received: 24 April 2001
Accepted: 11 October 2001

Abstract

Within the scope of a Key Programme determining fundamental parameters of stars observed by HIPPARCOS, spectra of 525 B8 to F2-type stars brighter than $V=8$ have been collected at ESO. Fourier transforms of several line profiles in the range 4200–4500 Å are used to derive $v\sin i$ from the frequency of the first zero. Statistical analysis of the sample indicates that measurement error is a function of $v\sin i$ and this relative error of the rotational velocity is found to be about 6% on average. The results obtained are compared with data from the literature. There is a systematic shift from standard values from [CITE], which are 10 to 12% lower than our findings. Comparisons with other independent $v\sin i$ values tend to prove that those from Slettebak et al. are underestimated. This effect is attributed to the presence of binaries in the standard sample of Slettebak et al., and to the model atmosphere they used.

Key words: techniques: spectroscopic / stars: early-type / stars: rotation

Based on observations made at the European Southern Observatory (ESO), La Silla, Chile, in the framework of the Key Programme 5-004-43K.