Radial velocities of early-type stars in the Perseus OB2 association^*

¹ Sterrewacht Leiden, Postbus 9513, 2300 RA Leiden, The Netherlands
² Now at SRON National Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands
³ Now at Astrophysics Missions Division, European Space Agency, ESTEC, Postbus 299, 2200 AG Noordwijk, The Netherlands
⁴ Now at Harvard–Smithsonian Center for Astrophysics, 60 Garden Street, MS 31, Cambridge, MA 02138, USA

Corresponding author: K. C. Steenbrugge, K.C.Steenbrugge@sron.nl

Received: 21 January 2003
Accepted: 19 February 2003

Abstract

We present radial velocities for 29 B- and A-type stars in the field of the nearby association Perseus OB2. The velocities are derived from spectra obtained with AURELIE, via cross correlation with radial velocity standards matched as closely as possible in spectral type. The resulting accuracy is ~2–3 km s^-1. We use these measurements, together with published values for a few other early-type stars, to study membership of the association. The mean radial velocity (and measured velocity dispersion) of Per OB2 is  km s^-1, and lies ~15 km s^-1 away from the mean velocity of the local disk field stars. We identify a number of interlopers in the list of possible late-B- and A-type members which was based on Hipparcos parallaxes and proper motions, and discuss the colour-magnitude diagram of the association.