论文标题
使用壳模型调查WN4 Star HD 50896中的结块
Using Shell Models to Investigate Clumping in the WN4 Star HD 50896
论文作者
论文摘要
狼射线（WR）恒星的光谱表现出源自风的强大，宽阔的排放线。这些风是辐射驱动的，并且容易受到导致团块形成的流体动力不稳定性。当WR恒星建模光谱时，通常采用填充因子（VFF）方法来处理块状风。但是，这是基于以下假设：整个风质量都位于光学薄的团块中，这不一定在浓风中是合理的。为了测试VFF方法的有效性，我们使用了先前描述的处理结块的方法，即“壳”方法，研究线和连续形成在WN4星的密集风中，HD 50896。我们的模型表明，完全完整的球形壳具有观察光谱的张力；发射线中的持续``dip''发生在线中心。删除此倾角要求我们的模型使用``损坏''壳 - 侧面高度校正的壳。这暗示了HD 50896的风，以及其他WR恒星的风，由小的侧向限制和径向压缩的团块组成 - 团块比Sobolev长度小。我们讨论了VFF方法有效所需的一些条件。
The spectra of Wolf-Rayet (WR) stars exhibit strong, broad emission lines that originate in the wind. These winds are radiatively driven and are susceptible to hydrodynamic instabilities that result in the formation of clumps. When modelling spectra of WR stars the volume-filling factor (VFF) approach is usually employed to treat clumpy winds. However, it is based on the assumption that the entire wind mass resides in optically thin clumps, which is not necessarily justifiable in dense winds. To test the validity of the VFF approach we use a previously described method of treating clumping, the ``Shell'' approach, to study line and continuum formation in the dense wind of the WN4 star, HD 50896. Our models indicate that fully intact spherical shells are in tension with observed spectra; a persistent ``dip'' in emission lines occurs at line centre. Removing this dip requires our models to use ``broken'' shells -- shells that are highly decoherent laterally. This insinuates that the wind of HD 50896, and by extension the winds of other WR stars, are comprised of small laterally confined and radially compressed clumps -- clumps smaller than the Sobolev length. We discuss some of the conditions necessary for the VFF approach to be valid.
