Massive Stars as Tracers for Stellar and Galactochemical Evolution (With 22 Figures)
Massive Stars as Tracers for Stellar and Galactochemical Evolution (With 22 Figures)
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大质量恒星作为恒星和半乳化学演化示踪剂（含 22 个数字）
DOI：
10.1002/9783527622993.ch14
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发表时间：
2008
影响因子：
6.5
通讯作者：
N. Przybilla
中科院分区：
文献类型：
--
作者：
N. Przybilla
炽热的大质量恒星是物质宇宙循环的关键驱动力。它们是星际介质能量和动量收支的主要贡献者，通过电离辐射、恒星风和超新星爆炸，它们是核合成的重要场所。由于它们的高亮度，这些恒星是远距离光谱的主要目标。有了现在这一代的8-10M级望远镜和现代仪器，它们可以作为强大的示踪剂，在整个银河系、本星系群的其他恒星形成星系以及更远的地方用作化学成分的示踪剂。我们特别感兴趣的是最常见的大质量恒星，即质量在8-30M⊙之间的OB型恒星，从主序列到BA型超巨星的演化阶段，人们对它们的研究是均匀的。在过去，对早期类型恒星的定量研究不够准确(例如，元素丰度最多只能在~2倍的范围内)，无法得出决定性的结果。现在，定量光谱学的进步使恒星参数和化学丰度的约束比以前可能的精度要高得多：有效温度的不确定度为%1-2%，(对数)表面重力的不确定度为0.05-0.10dex，丰度为~10-25%(随机)加~25%(系统1σ误差)。这是通过使用改进的原子数据以及识别和随后减少系统误差来实现的。大质量恒星因此变成了现代天体物理学的万能工具。改进的大气模型分析对我们理解大质量恒星的演化和星系的化学演化有很大的影响，因为可以第一次得出彻底的结论。我们讨论了大质量恒星作为示踪剂：i)轻元素的丰度，这使得研究恒星内部复杂的(磁)流体动力学混合过程的影响成为可能；ii)重元素的丰度，这使得研究今天银河系中金属的空间分布成为可能。最后，讨论了在本星系群内外的其他星系中研究大质量超巨星的第一个结果。特别提请注意银河系丰度梯度和一种新的光谱距离测定技术。
Hot, massive stars are key drivers of the cosmic cycle of matter. They are the dominant contributors to the energy and momentum budget of the interstellar medium, via ionizing radiation, stellar winds and supernova explosions, and they are important sites of nucleosynthesis. Because of their high luminosities these stars are primary targets for spectroscopy over large distances. With the present generation of 8–10m-class telescopes and modern instruments they can be used as powerful tracers of chemical composition throughout the Milky Way, other star-forming galaxies of the Local Group, and beyond. The most frequent massive stars, OB-type stars in the mass range from about 8 to 30 M⊙, are of particular interest to us, which are studied in a homogeneous way from the main sequence to the evolved stage as BA-type supergiants. In the past, quantitative studies of early-type stars were not accurate enough (eg only to within a factor~ 2 at most for elemental abundances) to derive conclusive results. Now, advances in quantitative spectroscopy allow stellar parameters and chemical abundances to be constrained with much higher precision than previously possible: to% 1–2% uncertainty in effective temperature, 0.05–0.10 dex in (logarithmic) surface gravity, and~ 10–25%(random) plus~ 25%(systematic 1σ-errors) in abundance. This is achieved by the use of improved atomic data and the identification and consequent reduction of systematic errors. Massive stars are thus turned into universal tools for modern astrophysics. The improved model atmosphere analyses have a strong impact on our understanding of the evolution of massive stars and the chemical evolution of galaxies, as thorough conclusions can be drawn for the first time. We discuss massive stars as tracers for: I) abundances of the light elements, which make possible the study of the effects of complex (magneto) hydrodynamic mixing processes in the stellar interior; II) the abundances of the heavier elements, which allow the present-day spatial distribution of metals in the Milky Way to be investigated. Finally, first results from studies of massive supergiants in other galaxies within the Local Group and beyond are discussed. Attention is drawn in particular to galactic abundance gradients and a novel spectroscopic distance determination technique.
VLT-FLAMES 大质量恒星巡天：以麦哲伦星云团 NGC 330、NGC 346、NGC 2004 和 N11 区域为中心的观测
影响因子：
6.5
作者：
Evans C
通讯作者：
Evans C