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Issue A&A
Volume 393, Number 3, October III 2002
Page(s) 897 - 911
Section Formation, structure and evolution of stars
DOI 10.1051/0004-6361:20020943



A&A 393, 897-911 (2002)
DOI: 10.1051/0004-6361:20020943

Rotational velocities of A-type stars

II. Measurement of ${v\sin i}$ in the northern hemisphere
F. Royer1, 2, S. Grenier2, M.-O. Baylac2, A. E. Gómez2 and J. Zorec3

1  Observatoire de Genève, 51 chemin des Maillettes, 1290 Sauverny, Switzerland
2  GEPI/CNRS FRE 2459, Observatoire de Paris, 5 place Janssen, 92195 Meudon Cedex, France
3  CNRS, Institut d'Astrophysique de Paris, 98bis boulevard Arago, 75014 Paris, France

(Received 25 February 2002 / Accepted 19 June 2002)

Abstract
This work is the second part of the set of measurements of ${v\sin i}$ for A-type stars, begun by Royer et al. ([CITE]). Spectra of 249 B8 to F2-type stars brighter than V=7 have been collected at Observatoire de Haute-Provence (OHP). Fourier transforms of several line profiles in the range 4200-4600 Å are used to derive ${v\sin i}$ from the frequency of the first zero. Statistical analysis of the sample indicates that measurement error mainly depends on ${v\sin i}$ and this relative error of the rotational velocity is found to be about 5% on average. The systematic shift with respect to standard values from Slettebak et al. ([CITE]), previously found in the first paper, is here confirmed. Comparisons with data from the literature agree with our findings: ${v\sin i}$ values from Slettebak et al. are underestimated and the relation between both scales follows a linear law ${v\sin i}_{\rm new} = 1.03\,{v\sin i}_{\rm old}+7.7$. Finally, these data are combined with those from the previous paper (Royer et al. [CITE]), together with the catalogue of Abt & Morrell ([CITE]). The resulting sample includes some 2150 stars with homogenized rotational velocities.


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

Offprint request: F. Royer, frederic.royer@obs.unige.ch

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