标题： 大质量恒星风的宽带X射线吸收建模 显示英文标题

标题： Modeling broadband X-ray absorption of massive star winds

摘要： 我们提出了一种计算由大质量恒星部分光学厚风中冲击加热等离子体发射的X射线净传输的方法。通过假设在某个最小半径以上，发射等离子体和吸收等离子体以恒定的质量比混合，在该半径以下假定没有发射，我们通过对形式解进行精确积分来求得透射率。此模型比与风基部日冕相关的平板吸收或假设所有观测到的X射线都从光学深度为一的半径以上无衰减发射出去的外逸层近似更现实。我们的模型已在XSPEC中实现为预计算表格，可以与用户定义的波长相关风吸收率表耦合。我们提供了一个默认的风吸收率模型，它比常用的中性星际介质（ISM）表格更能代表真实的风吸收率。初步的\textit{钱德拉}光栅数据建模表明，OB型恒星根据光谱亚型的X射线硬度趋势主要可以理解为风吸收效应。 显示英文摘要

摘要： We present a method for computing the net transmission of X-rays emitted by shock-heated plasma distributed throughout a partially optically thick stellar wind from a massive star. We find the transmission by an exact integration of the formal solution, assuming that the emitting plasma and absorbing plasma are mixed at a constant mass ratio above some minimum radius, below which there is assumed to be no emission. This model is more realistic than either the slab absorption associated with a corona at the base of the wind or the exospheric approximation that assumes that all observed X-rays are emitted without attenuation from above the radius of optical depth unity. Our model is implemented in XSPEC as a pre-calculated table that can be coupled to a user-defined table of the wavelength dependent wind opacity. We provide a default wind opacity model that is more representative of real wind opacities than the commonly used neutral interstellar medium (ISM) tabulation. Preliminary modeling of \textit{Chandra} grating data indicates that the X-ray hardness trend of OB stars with spectral subtype can largely be understood as a wind absorption effect.