NOAO >   Observing Info >   Approved Programs >   2001B-0151

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Proposal Information for 2001B-0151


PI: Jean-Claude Mermilliod, University of Lausanne, Jean-Claude.Mermilliod@obs.unige.ch
Address: Observatoire, Chavannes-des-Bois, Vaud CH-1290, Switzerland

CoI: Claudio Melo, Geneva Observatory
CoI: Pierre North, University of Lausanne
CoI: Frederic Royer, Geneva Observatory
CoI: Robert D. Mathieu, University of Wisconsin - Madison

Title: Rotation of B-type stars in h & (chi) Persei (NGC 869/884)

Abstract: This proposal is part of a program aimed at measuring rotational velocities of B-type stars in open clusters with a range of metallicities. The primary purpose is to investigate the dependance of the rotational-velocity distribution on metallicity and explain the strong relation found by Maeder et al. (1999, A&A 346, 459) between the Be/(B+Be) ratio and metallicity, based on open clusters in our Galaxy and the Magellanic Clouds. More precisely, we shall determine the projected rotational velocities of a complete sample of ~ 260 B- and early A-type stars in the open clusters NGC 869 and NGC 884 (h and (chi) Persei), which are in the external part of the Galaxy and slightly metal-poor relative to the Sun ([Fe/H]=-0.30). These data will provide an important point and bridge the gap between the metal- rich clusters in the direction of the Galactic center (to be observed at ESO in april 2001) and the metal-poor ones of the LMC and SMC that we intend to observe later on.


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



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