Normal A0−A1 stars with low rotational velocities
1 GEPI/CNRS UMR 8111, Observatoire de Paris − Université Paris Denis Diderot, 5 place Jules Janssen, 92190 Meudon, France
2 Department of Physics and Astronomy, Notre Dame University-Louaize, PO Box 72, Zouk Mikaël, Lebanon
3 LESIA/CNRS UMR 8109, Observatoire de Paris − Université Pierre et Marie Curie − Université Paris Denis Diderot, 5 place Jules Janssen, 92190 Meudon, France
4 Laboratoire Lagrange, Université de Nice Sophia Antipolis, Parc Valrose, 06100 Nice, France
5 Department of Physics, The Citadel, 171 Moultrie Street, Charleston, SC 29409, USA
6 Astrophysics Group, Keele University, Staffordshire ST5 5BG, UK
7 INSUGEO-CONICET, Tucumán, Argentina
8 Institut für Astrophysik Göttingen, Physik Fakultät, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
9 18A Stratford St, 1071 Auckland, New Zealand
10 Department of Physics and Astronomy, Brandon University, Brandon, MB R7A 6A9, Canada
Received: 27 September 2013
Accepted: 23 December 2013
Context. The study of rotational velocity distributions for normal stars requires an accurate spectral characterization of the objects in order to avoid polluting the results with undetected binary or peculiar stars. This piece of information is a key issue in the understanding of the link between rotation and the presence of chemical peculiarities.
Aims. A sample of 47 low vsini A0−A1 stars (vsini < 65 km s-1), initially selected as main-sequence normal stars, are investigated with high-resolution and high signal-to-noise spectroscopic data. The aim is to detect spectroscopic binaries and chemically peculiar stars, and eventually establish a list of confirmed normal stars.
Methods. A detailed abundance analysis and spectral synthesis is performed to derive abundances for 14 chemical species. A hierarchical classification, taking measurement errors into account, is applied to the abundance space and splits the sample into two different groups, identified as the chemically peculiar stars and the normal stars.
Results. We show that about one third of the sample is actually composed of spectroscopic binaries (12 double-lined and five single-lined spectroscopic binaries). The hierarchical classification breaks down the remaining sample into 13 chemically peculiar stars (or uncertain) and 17 normal stars.
Key words: stars: early-type / stars: rotation / stars: abundances / stars: chemically peculiar / binaries: spectroscopic
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