银河系OB-星的L-带光谱
L-band spectroscopy of Galactic OB-stars
摘要：
上下文通过辐射驱动的超音速风发生的质量损失是大质量恒星演化过程中的一个关键问题。两个突出的问题是目前的挑战理论的辐射驱动的风：风丛生和弱风问题。目标。我们试图获得准确的质量损失率OB星在不同的进化阶段，以限制我们目前的理解大规模星风的影响，这两个问题。方法.我们进行多波长的定量分析的样本的10个银河系OB-星的大气代码CMFGEN的装置，特别强调的L-波段窗口。对Brα和Pfγ作为质量损失和凝聚诊断的潜力进行了详细的研究。结果对于风密集的物体，Brα对中间风进行采样，而Pfγ则映射内部风。结合其他指标（UV，Hα，Brγ），这些线使我们能够限制风聚集结构，并获得“真正的”质量损失率。对于具有弱风的物体，Brα成为约束质量损失率的可靠诊断工具。叠加在相当浅的斯塔克吸收翼上的线多普勒核心处的发射分量对已经在非常低的质量损失值下的质量损失反应非常敏感。另一方面，线翼显示出与经典光学质量损失诊断Hα相似的质量损失敏感性。结论.我们的研究揭示了巨大的诊断潜力的L-波段光谱得出的聚集性和热星风的质量损失率。我们相信Brα将成为以前所未有的准确度测量非常低的质量损失率的主要诊断工具
英文摘要：
Context. Mass-loss, occurring through radiation driven supersonic winds, is a key issue throughout the evolution of massive stars. Two outstanding problems are currently challenging the theory of radiation-driven winds: wind clumping and the weak-wind problem. Aims. We seek to obtain accurate mass-loss rates of OB stars at different evolutionary stages to constrain the impact of both problems in our current understanding of massive star winds. Methods. We perform a multi-wavelength quantitative analysis of a sample of ten Galactic OB-stars by means of the atmospheric code CMFGEN, with special emphasis on the L-band window. A detailed investigation is carried out on the potential of Brα and Pfγ as mass-loss and clumping diagnostics. Results. For objects with dense winds, Brα samples the intermediate wind while Pfγ maps the inner one. In combination with other indicators (UV, Hα, Brγ) these lines enable us to constrain the wind clumping structure and to obtain "true" mass-loss rates. For objects with weak winds, Brα emerges as a reliable diagnostic tool to constrain the mass-loss rates. The emission component at the line Doppler-core superimposed on the rather shallow Stark absorption wings reacts very sensitively to mass loss already at very low mass-loss values. On the other hand, the line wings display similar sensitivity to mass loss as Hα, the classical optical mass loss diagnostics. Conclusions. Our investigation reveals the great diagnostic potential of L-band spectroscopy to derive clumping properties and mass-loss rates of hot star winds. We are confident that Brα will become the primary diagnostic tool to measure very low mass-loss rates with unprecedented accuracy
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