期刊
ASTRONOMICAL JOURNAL
卷 144, 期 1, 页码 -出版社
IOP PUBLISHING LTD
DOI: 10.1088/0004-6256/144/1/2
关键词
Local Group; stars: variables: general; supergiants
资金
- NSF
- National Aeronautics and Space Administration
- National Science Foundation [AST-1008020]
- NASA by the Chandra X-ray Center [PF0-110075, NAS8-03060]
- Direct For Mathematical & Physical Scien
- Division Of Astronomical Sciences [1008020] Funding Source: National Science Foundation
We present moderate-resolution spectroscopic observations of red supergiants (RSGs) in the low-metallicity Local Group galaxies NGC 6822 (Z = 0.4Z(circle dot)) and Wolf-Lundmark-Melotte (WLM; Z = 0.1Z(circle dot)). By combining these observations with reduction techniques for multislit data reduction and flux calibration, we are able to analyze spectroscopic data of 16 RSGs in NGC 6822 and spectrophotometric data of 11 RSGs in WLM. Using these observations, we determine spectral types for these massive stars, comparing them to Milky Way and Magellanic Cloud RSGs and thus extending observational evidence of the abundance-dependent shift of RSG spectral types to lower metallicities. In addition, we have uncovered two RSGs with unusually late spectral types (J000158.14-152332.2 in WLM, with a spectral type of M3 I, and J194453.46-144552.6 in NGC 6822, with a spectral type of M4.5 I) and a third RSG (J194449.96-144333.5 in NGC 6822) whose spectral type has varied from an M2.5 in 1997 to a K5 in 2008. All three of these stars could potentially be members of a recently discovered class of extreme RSG variables.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据