Gemini observations of Wolf-Rayet stars in the Local Group starburst galaxy IC 10

被引:60
作者
Crowther, PA
Drissen, L
Abbott, JB
Royer, P
Smartt, SJ
机构
[1] UCL, Dept Phys & Astron, London WC1E 6BT, England
[2] Univ Laval, Dept Phys, Quebec City, PQ G1K 7P4, Canada
[3] Observ Mont Megant, London WC1E 6BT, England
[4] Univ Liege, Inst Astrophys, B-4000 Liege, Belgium
[5] Katholieke Univ Leuven, Inst Sterrunkunde, B-3001 Louvain, Belgium
[6] Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England
关键词
galaxies : individual : IC 10; galaxies : starburst; stars : evolution; stars : Wolf-Rayet;
D O I
10.1051/0004-6361:20030503
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We present Gemini-N GMOS and CFHT MOS spectroscopy of Wolf-Rayet candidates in the Local Group dwarf galaxy IC 10 that were previously identified by Massey et al. and Royer et al. From the present spectroscopic survey, the WC/WN ratio for IC 10 remains unusually high, given its low metallicity, although none of the WC9 stars suspected from narrow-band imaging are confirmed. Our spectroscopy confirms 9 newly discovered Wolf-Rayet candidates from Royer et al., whilst spectral types of 14 Wolf-Rayet stars previously observed by Massey & Armandroff are refined here. In total, there are 26 spectroscopically confirmed Wolf-Rayet stars in IC 10. All but one of the fourteen WC stars are WC4-6 stars, the exception being # 10 from Massey et al., a broad-lined, apparently single WC7 star. There are a total of eleven WN stars, which are predominantly early WN3-4 stars, but include a rare WN10 star, # 8 from Royer et al. # 5 from Massey et al. is newly identified as a transition WN/C star. Consequently, the WC/WN ratio for IC10 is 14/11similar to1.3, unusually high for a metal-poor galaxy. Re-evaluating recent photometric data of Massey & Holmes, we suggest that the true WC/WN ratio may not be as low as similar to0.3. Finally, we present ground-based finding charts for all confirmed WR stars, plus HST/WFPC2 charts for twelve cases.
引用
收藏
页码:483 / 493
页数:11
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