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A study of the B and Be star population in the field of the LMC open cluster NGC2004 with VLT-FLAMES

Christophe Martayan·Anne-Marie Hubert·Michele Floquet·Juan Fabregat·Yves Fremat·Coralie Neiner·Philippe Stee·Jean Zorec
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Abstract

Observations of hot stars belonging to the young cluster LMC-NGC2004 and its surrounding region have been obtained with the VLT-GIRAFFE facilities in MEDUSA mode. 25 Be stars were discovered; the proportion of Be stars compared to B-type stars is found to be of the same order in the LMC and in the Galaxy fields. 23 hot stars were discovered as spectroscopic binaries (SB1 and SB2), 5 of these are found to be eclipsing systems from the MACHO database, with periods of a few days. About 75% of the spectra in our sample are polluted by hydrogen (Halpha and Hgamma), [SII] and [NII] nebular lines. These lines are typical of HII regions. They could be associated with patchy nebulosities with a bi-modal distribution in radial velocity, with higher values (+335 kms^{-1}) preferentially seen inside the southern part of the known bubble LMC4 observed in HI at 21 cm.

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Christophe Martayan, Anne-Marie Hubert, Michele Floquet, Juan Fabregat, Yves Fremat, Coralie Neiner, Philippe Stee, Jean Zorec. 2005-09-13. A study of the B and Be star population in the field of the LMC open cluster NGC2004 with VLT-FLAMES. https://doi.org/10.1051/0004-6361%3A20052760

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