Red giants in open clusters - XIV. Mean radial velocities for 1309 stars and 166 open clusters (original) (raw)

A&A 485, 303-314 (2008)

XIV. Mean radial velocities for 1309 stars and 166 open clusters

1 Laboratoire d'Astrophysique de l'École polytechnique fédérale de Lausanne (EPFL), Observatoire, 1290 Versoix, Switzerland e-mail: Jean-Claude.Mermilliod@epfl.ch
2 Observatoire de Genève, 51 Ch. des Maillettes, 1290 Sauverny, Switzerland

Received: 27 February 2008
Accepted: 21 March 2008

Abstract

Context. Radial velocities have proved to be an efficient method for membership determination if there are at least 2 or 3 red giants in a cluster. They are necessary for galactic studies, but are still missing for many open clusters.

Aims. We present the final catalogues of a long-term observing programme performed with the two coravel spectrovelocimeters for red giants in open clusters. The main aims were to detect spectroscopic binaries and determine their orbital parameters, determine the membership, and compute mean velocities for the stars and open clusters.

Methods. We computed weighted mean radial velocities for 1309 stars from 10 517 individual observations, including the systemic radial velocities from spectroscopic orbits and for cepheids.

Results. The final results are contained in three catalogues collecting 10 517 individual radial velocities, mean radial velocities for 1309 red giants, and mean radial velocities for 166 open clusters among which there are 57 new determinations. We identified 891 members and 418 non-members. We discovered a total of 288 spectroscopic binaries, among which 57 are classified as non-members. In addition 27 stars were judged to be variable in radial velocities and they are all red supergiants.

Conclusions. The present material, combined with recent absolute proper motions, will permit various investigation of the galactic distribution and space motions of a large sample of open clusters. However, the distance estimates still remain the weakest part of the necessary data. This paper is the last one in this series devoted to the study of red giants in open clusters based on radial velocities obtained with the coravel instruments.

Key words: Galaxy: open clusters and associations: general / techniques: radial velocities / stars: late-type

Based on observations collected at the Haute-Provence Observatory (France) and on observations collected with the Danish 1.54-m telescopes at the European Southern Observatory, La Silla, Chile.

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