Coupling hydrodynamics with comoving frame radiative transfer - I. A unified approach for OB and WR stars
Coupling hydrodynamics with comoving frame radiative transfer - I. A unified approach for OB and WR stars
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流体动力学与共动框架辐射传输的耦合 - I OB 和 WR 星的统一方法
DOI：
10.1051/0004-6361/201730642
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发表时间：
2017
影响因子：
6.5
通讯作者：
Shenar
中科院分区：
文献类型：
--
作者：
Sander;A. A. C;Hamann;Hainich;Shenar
背景二十多年来，恒星大气代码一直用于推导大质量恒星的恒星和风参数。虽然它们已经成为一个强大的工具，并充分再现所观察到的光谱外观，它们几乎不能用于测量参数以上。一个主要的障碍是他们之间的不一致性计算的辐射场和风分层由于使用规定的质量损失率和风velocityfield.AimsWe提出的概念，新一代的流体动力学一致的非本地的热平衡（非LTE）恒星大气模型，允许辐射驱动的恒星风的详细研究。作为第一个演示，这种新的模型被应用到一个大规模的O星星。MethodsBased上以前的工作，PoWR代码已被扩展的选项，始终解决流体动力学方程与统计方程和辐射传输，以获得流体动力学一致的大气层结。在这些模型中，整个速度场迭代更新连同调整的质量损失率。ResultsThe概念获得流体力学一致的模型，使用comoving帧辐射传输概述。为了提供一个有用的基准，我们提出了一个演示模型，这是出于描述研究得很好的O 4超巨星O2 Pup。所获得的恒星和风参数是在目前的范围内的文献value.ConclusionsFor第一次，PoWR代码已被用来获得一个大规模的O星星流体动力学一致的模型。这是通过对早期用于沃尔夫-拉叶星的概念进行深刻修改而实现的。速度场是由各种因素形成的，这些因素对辐射加速度有贡献，特别是在外部风中。结果进一步表明，对于更密集的风，会出现偏离标准β定律的情况。
ContextFor more than two decades, stellar atmosphere codes have been used to derive the stellar and wind parameters of massive stars. Although they have become a powerful tool and sufficiently reproduce the observed spectral appearance, they can hardly be used for more than measuring parameters. One major obstacle is their inconsistency between the calculated radiation field and the wind stratification due to the usage of prescribed mass-loss rates and wind-velocity fields.AimsWe present the concepts for a new generation of hydrodynamically consistent non-local thermodynamical equilibrium (non-LTE) stellar atmosphere models that allow for detailed studies of radiation-driven stellar winds. As a first demonstration, this new kind of model is applied to a massive O star.MethodsBased on earlier works, the PoWR code has been extended with the option to consistently solve the hydrodynamic equation together with the statistical equations and the radiative transfer in order to obtain a hydrodynamically consistent atmosphere stratification. In these models, the whole velocity field is iteratively updated together with an adjustment of the mass-loss rate.ResultsThe concepts for obtaining hydrodynamically consistent models using a comoving-frame radiative transfer are outlined. To provide a useful benchmark, we present a demonstration model, which was motivated to describe the well-studied O4 supergiantζPup. The obtained stellar and wind parameters are within the current range of literature values.ConclusionsFor the first time, the PoWR code has been used to obtain a hydrodynamically consistent model for a massive O star. This has been achieved by a profound revision of earlier concepts used for Wolf-Rayet stars. The velocity field is shaped by various elements contributing to the radiative acceleration, especially in the outer wind. The results further indicate that for more dense winds deviations from a standardβ-law occur.
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DOI：
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发表时间：
1995
期刊：
影响因子：
--
作者：
K. Gayley
通讯作者：
K. Gayley
DOI：
10.1086/305350
发表时间：
1998-03
期刊：
The Astrophysical Journal
影响因子：
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作者：
D. Hillier;Doug L. Miller
通讯作者：
D. Hillier;Doug L. Miller
DOI：
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发表时间：
2008
期刊：
影响因子：
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作者：
P. Muller;J. Vink
通讯作者：
J. Vink
通过光谱分析限制大质量恒星的演化。
DOI：
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发表时间：
1999
期刊：
影响因子：
--
作者：
D. Hillier;Douglas L. Miller
通讯作者：
Douglas L. Miller
金属丰度极低的热星的线驱动风、电离通量和紫外光谱。
DOI：
--
发表时间：
2003
期刊：
影响因子：
--
作者：
K. Weis;W. Duschl;S. Keller;M. Bessell;K. Cook;M. Geha
通讯作者：
M. Geha