标题： 在巨银河星团韦斯特兰1中的一个隐藏的沃尔夫-拉叶星群体 显示英文标题

标题： A hidden population of Wolf-Rayet stars in the massive galactic cluster Westerlund 1

摘要： 我们报告在年轻的银河系疏散星团Westerlund 1中发现了一种此前未被检测到的沃尔夫-拉叶星群体。 对该星团的光学光谱观测确定了11个此类天体；初步分类表明，其中6个是氮丰富的（WN型），5个是碳丰富的（WC型）。 包括之前识别出的蓝超巨星、黄超巨星和红超巨星，Westerlund 1显然拥有非常丰富的大质量主序后天体群体。 到目前为止，Westerlund 1的主序后天体群体明显大于其他任何银河系年轻疏散星团——可能除了Arches星团之外——这意味着它可能是本地集团中迄今为止识别出的最庞大的年轻星团之一。 显示英文摘要

摘要： We report the discovery of a hitherto undetected population of Wolf-Rayet stars in the young galactic open cluster Westerlund 1. Optical spectroscopy of the cluster identified 11 such objects; provisional classification suggests that 6 are nitrogen rich (WN) and 5 carbon rich (WC). Including the previously identified Blue, Yellow and Red Super- & Hypergiants, Westerlund 1 clearly has a very rich population of massive post-Main Sequence objects. To date, the post-MS population of Westerlund 1 is significantly larger than that of any other galactic young open cluster - with the possible exception of the Arches - implying that it is potentially amongst the most massive young clusters yet identified in the Local Group.