标题： 哈勃空间望远镜/STIS分解R136星团。 I. 远紫外光谱普查和年轻星团中HeII 1640的起源 显示英文标题

标题： The R136 star cluster dissected with Hubble Space Telescope/STIS. I. Far-ultraviolet spectroscopic census and the origin of HeII 1640 in young star clusters

摘要： 我们介绍了R136a的HST/STIS恒星普查，这是30 Doradus中心的电离星团。 我们提供了使用17个连续52x0.2角秒狭缝对R136进行的低分辨率远紫外STIS/MAMA光谱观测，这些狭缝共同提供了对R136中心0.85秒差距（3.4角秒）的完整覆盖。 我们提供了半径0.5秒差距内57个源中90%的光谱类型，这些源的m_F555W = 16.0星等，以及包括R136b（O4 If/WN8）在内的8个额外附近源。 我们测量了52颗早期型恒星的风速，来自CIV 1548-51，包括16颗O2-3星。 我们首次对Weigelt & Baier的R136a成员进行了光谱分类，其中包括三颗WN5星（a1-a3）、两颗O超巨星（a5-a6）和三颗早期O矮星（a4, a7, a8）。 我们提供了R136中最重的O星的完整赫茨普龙-罗素图，从中我们得到了星团年龄为1.5+0.3_-0.7 Myr。 此外，我们讨论了R136的综合紫外光谱，并强调了最明亮的恒星在产生显著的HeII 1640发射线中的核心作用。 这种发射完全由初始质量高于约100 Msun的非常大质量恒星主导。 在非常年轻的星团（例如NGC 3125中的A1）的综合光中存在强烈的HeII 1640发射线，这支持了一个初始质量函数延伸超过传统上限100 Msun。 我们在附录中包含了LMC O星的紫外光谱蒙太奇。 本系列的未来研究将集中在光学STIS/CCD中分辨率观测上。 显示英文摘要

摘要： We introduce a HST/STIS stellar census of R136a, the central ionizing star cluster of 30 Doradus. We present low resolution far-ultraviolet STIS/MAMA spectroscopy of R136 using 17 contiguous 52x0.2 arcsec slits which together provide complete coverage of the central 0.85 parsec (3.4 arcsec). We provide spectral types of 90% of the 57 sources brighter than m_F555W = 16.0 mag within a radius of 0.5 parsec of R136a1, plus 8 additional nearby sources including R136b (O4\,If/WN8). We measure wind velocities for 52 early-type stars from CIV 1548-51, including 16 O2-3 stars. For the first time we spectroscopically classify all Weigelt & Baier members of R136a, which comprise three WN5 stars (a1-a3), two O supergiants (a5-a6) and three early O dwarfs (a4, a7, a8). A complete Hertzsprung-Russell diagram for the most massive O stars in R136 is provided, from which we obtain a cluster age of 1.5+0.3_-0.7 Myr. In addition, we discuss the integrated ultraviolet spectrum of R136, and highlight the central role played by the most luminous stars in producing the prominent HeII 1640 emission line. This emission is totally dominated by very massive stars with initial masses above ~100 Msun. The presence of strong HeII 1640 emission in the integrated light of very young star clusters (e.g A1 in NGC 3125) favours an initial mass function extending well beyond a conventional upper limit of 100 Msun. We include montages of ultraviolet spectroscopy for LMC O stars in the Appendix. Future studies in this series will focus on optical STIS/CCD medium resolution observations.