Spectroscopy of Massive Stars in the Double Cluster h/chi Persei

大质量恒星是星系演化的主要驱动力，它们通过星风和超新星向星际介质输入能量和动量，是核合成的重要场所，深入了解大质量恒星的内部结构和演化对天体物理学的各个领域都具有重要意义。其中，大质量恒星的演化模型为解释星星团和星系中的恒星种群提供了基础。它们描述了超新星祖先的结构，并允许预测化学产额。它们是解释中子星、恒星黑洞和某些类型的伽马射线爆发等奇异现象的起点。通过考虑旋转效应，在大质量星星演化的建模方面取得了巨大进展。越来越多的证据表明，旋转和质量损失是塑造整个宇宙历史中大质量恒星演化的物理关键因素。目前的模型对表面性质进行了详细的预测在高光谱分辨率和极高信号-时间分辨率条件下对英仙座h和chi星系团中的大质量星星群体进行了观测，并对观测结果进行了分析。噪声比将进行，以获得严格的observationalconstraints恒星演化模型。均匀的样品将涵盖所有的演化阶段，从主序列上的巨人到超巨星阶段，在一个明确的环境，独特的年龄和金属丰度，包括慢和快旋转。使用复杂的非LTE建模和一种新的分析方法将以前所未有的准确度和精度提供恒星参数和化学丰度。轻元素（He，C，N，O）的表面丰度将特别用于验证最近受到挑战的旋转混合概念的基础上最小化的观测偏差的样本。我们要求旅行的钱，以进行观测运行在卡拉尔阿尔托天文台，其中五个晚上的观测时间已被授予与Echelle摄谱仪CAFE的2.2米望远镜。

Massive stars are main drivers of the evolution of galaxies because of their energy and momentum input into the interstellar medium through stellar winds and supernovae, and they are important sites of nucleosynthesis.The development of a detailed understanding of their inner structure and evolution is of utmost importance for wide fields of astrophysics. Among many others, evolution models of massive stars provide the basis for the interpretation of stellar populations in star clusters and galaxies. They describe the structure of supernova progenitors and allow chemical yields to be predicted. And, they are the starting point for explaining exotic phenomena such as neutron stars, stellar black holes and some types of gamma-ray bursts.Enormous progress has been made in the modelling of massive star evolution by accounting for the effects of rotation. There is a growing body of evidence that rotation together with mass loss are the physical key ingredients shaping the evolution of massive stars throughout cosmic history. The current models make detailed predictions on the surface properties (stellar parameters and chemical abundances) of massive stars that need to be compared to detailed observations for verification of the assumptions made in the models.A survey of the massive star population in the Galactic double cluster h and chi Persei at high spectralresolution and very high signal-to-noise ratio will be undertaken in order to derive tight observationalconstraints on stellar evolution models. The homogeneous sample will cover all evolutionary stages from the main sequence over the giant to the supergiant stage in a well-defined environment of unique age andmetallicity, comprising slow and fast rotators. Use of sophisticated non-LTE modelling and a novel analysismethodology will provide stellar parameters and chemical abundances at unprecedented accuracy andprecision. Surface abundances of the light elements (He, C, N, O) will in particular be used to verify therecently challenged concept of rotational mixing based on a sample of minimised observational bias.We ask for travel money in order to conduct the observing run at Calar Alto Observatory, for which five nights of observing time have been granted with the Echelle spectrograph CAFE on the 2.2m telescope.