The stellar wind velocity field of HD 77581
The stellar wind velocity field of HD 77581
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HD 77581的恒星风速场
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
R. Walter
中科院分区：
文献类型：
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作者：
A. Manousakis;R. Walter
大质量恒星中星风的早期加速受到的约束很差。脉冲星发射的硬X射线光子在大质量X射线双星船帆座X-1中的散射可以用来探测其超巨星伴星HD 77581表面附近的恒星风速度和密度分布。
我们建立了一个高信噪比和高分辨率的硬X射线光曲线船帆座X-1测量雨燕/BAT超过300个轨道周期的系统，并将其与网格的流体动力学模拟的预测。
我们得到一个很好的协议之间的观测和模拟的一组狭窄的参数，这意味着接近恒星表面的风速是通常假设的标准β定律的两倍。局部速度梯度为$etasim0.5美元是有利的。即使还不完整，流体动力学模拟也成功地再现了船帆座X-1的几个观测特性。
The early acceleration of stellar winds in massive stars is poorly constrained. The scattering of hard X-ray photons emitted by the pulsar in the high-mass X-ray binary Vela X-1 can be used to probe the stellar wind velocity and density profile close to the surface of its supergiant companion HD 77581.
We built a high signal-to-noise and high resolution hard X-ray lightcurve of Vela X-1 measured by Swift/BAT over 300 orbital periods of the system and compared it with the predictions of a grid of hydrodynamic simulations.
We obtain a very good agreement between observations and simulations for a narrow set of parameters, implying that the wind velocity close to the stellar surface is twice larger than usually assumed with the standard beta law. Locally a velocity gradient of $etasim0.5$ is favoured. Even if still incomplete, hydrodynamic simulations are successfully reproducing several observational properties of Vela X-1.