The VLT-FLAMES survey of massive stars: observations centered on the Magellanic Cloud clusters NGC 330, NGC 346, NGC 2004, and the N11 region


Autoria(s): Evans, C.J.; Lennon, D.J.; Smartt, Stephen; Trundle, Carrie
Data(s)

01/09/2006

Resumo

We present new observations of 470 stars using the Fibre Large Array Multi-Element Spectrograph ( FLAMES) instrument in fields centered on the clusters NGC330 and NGC346 in the Small Magellanic Cloud (SMC), and NGC2004 and the N11 region in the Large Magellanic Cloud (LMC). A further 14 stars were observed in the N11 and NGC330 fields using the Ultraviolet and Visual Echelle Spectrograph (UVES) for a separate programme. Spectral classifications and stellar radial velocities are given for each target, with careful attention to checks for binarity. In particular, we have investigated previously unexplored regions around the central LH9/LH10 complex of N11, finding similar to 25 new O-type stars from our spectroscopy. We have observed a relatively large number of Be-type stars that display permitted Fe II emission lines. These are primarily not in the cluster cores and appear to be associated with classical Be-type stars, rather than pre main-sequence objects. The presence of the Fe II emission, as compared to the equivalent width of Ha, is not obviously dependent on metallicity. We have also explored the relative fraction of Be- to normal B-type stars in the field-regions near to NGC330 and NGC2004, finding no strong evidence of a trend with metallicity when compared to Galactic results. A consequence of service observations is that we have reasonable time-sampling in three of our FLAMES fields. We find lower limits to the binary fraction of O- and early B-type stars of 23 to 36%. One of our targets (NGC346-013) is especially interesting with a massive, apparently hotter, less luminous secondary component.

Identificador

http://pure.qub.ac.uk/portal/en/publications/the-vltflames-survey-of-massive-stars-observations-centered-on-the-magellanic-cloud-clusters-ngc-330-ngc-346-ngc-2004-and-the-n11-region(390a2137-e1d1-4fac-9ad7-56845fe75287).html

http://dx.doi.org/10.1051/0004-6361

Idioma(s)

eng

Direitos

info:eu-repo/semantics/restrictedAccess

Fonte

Evans , C J , Lennon , D J , Smartt , S & Trundle , C 2006 , ' The VLT-FLAMES survey of massive stars: observations centered on the Magellanic Cloud clusters NGC 330, NGC 346, NGC 2004, and the N11 region ' Astronomy and Astrophysics , vol 456 , no. 2 , pp. 623-U123 . DOI: 10.1051/0004-6361

Palavras-Chave #/dk/atira/pure/subjectarea/asjc/1900/1912 #Space and Planetary Science
Tipo

article