Single or binary origin of Wolf-Rayet stars? Which mode is dominant?

项目涉及利用VLT（FORS）和Gemini（GMOS）获得的成像和光谱光学数据集，以识别附近星星形成星系（如NGC 6946）中的Wolf-Rayet恒星。沃尔夫-拉叶星是一种化学演化的大质量恒星，其大气层显示出核心H（He，N）和核心He（C，O）燃烧的产物，因此它们要么是通过单个大质量恒星（太阳邻域> 25 Msun）的强大星风产生的，要么是通过近距离大质量双星系统（> 8 Msun）的质量交换产生的。单WR星将位于或靠近年轻的星星形成区域（很少的百万年，与星云有关），而双WR星可能位于明显更老的区域（数十百万年，带状星云）。我们将能够比较WR星在螺旋星系上的电离区域的位置，以帮助解决这个问题。星系的WR数量将利用GAIA即将推出的DR 2，这将首次提供到附近银河系WR恒星的距离-迄今为止，这种方法主要限于麦哲伦云中贫金属的WR数量。目前还没有确定沃尔夫-拉叶星是否是剥离包层核心坍缩超新星的主要祖先，因此WR星和剥离ccSNe的空间位置也将进行比较。

Project involves exploitation of imaging and spectroscopic optical datasets obtained with the VLT (FORS) and Gemini (GMOS) to identify Wolf-Rayet stars in nearby star forming galaxies such as NGC6946. Wolf-Rayet stars are chemically evolved massive stars whose atmospheres exhibit the products of core H (He, N) and core He (C, O) burning, so arise either via powerful stellar winds from single high mass stars (> 25 Msun in Solar Neighbourhood) or mass exchange in close massive binary sysems (> 8 Msun). Single WR stars will be located within or close to young star forming regions (few Myr, with associated nebulosity) while binary WR stars may be located in significantly older (tens of Myr, lacing nebulosity). We will be able to compare the location of WR stars in face on spiral galaxies with respect to ionized regions to help address this question. Quantitative WR populations of galaxies will exploit upcoming DR2 from GAIA which will provide distances to nearby Milky Way WR stars for the first time - to date this approach has largely been limited to metal poor WR populations in the Magellanic Clouds. It is also not currently established whether Wolf-Rayet stars are the main progenitors to stripped envelope core-collapse supernovae, so comparisons between the spatial location of WR stars and stripped ccSNe will also be made.