Irradiated atmospheres of accreting magnetic white dwarfs with an application to the polar AM Herculis
Irradiated atmospheres of accreting magnetic white dwarfs with an application to the polar AM Herculis
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吸积磁性白矮星的辐照大气及其在极地 AM 武仙座中的应用
DOI：
10.1051/0004-6361:20054336
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发表时间：
2005
影响因子：
6.5
通讯作者：
B. Gaensicke
中科院分区：
文献类型：
--
作者：
M. Koenig;K. Beuermann;B. Gaensicke
我们提出了一个试点研究的吸积磁白色矮星的大气在紫外到红外波长的强通量照射。该模型使用了一个标准的LTE恒星大气代码，通过引入一个角度依赖的外部辐射源扩展。目前的结果是获得一个外部源的光谱形状的10 000 K黑体和一个自由可调的光谱通量。该模型提供了一个解释，在其高状态下，在原型极地AM武仙座观察到的大部分充满了莱曼线。它也证实了以下假设：（i）回旋辐射和其他辐射源的照射是极区中白色矮星吸积斑周围大的加热极帽的主要原因;（ii）大部分再处理光出现在远紫外线中，而不是像最初的简单理论所建议的那样出现在软X射线区域中。我们还简要讨论了硬X射线在加热极冠中所起的作用。
We present a pilot study of atmospheres of accreting magnetic white dwarfs irradiated by intense fluxes at ultraviolet to infrared wavelengths. The model uses a standard LTE stellar atmosphere code which is expanded by introducing an angle-dependent external radiation source. The present results are obtained for an external source with the spectral shape of a 10 000 K blackbody and a freely adjustable spectral flux. The model provides an explanation for the observed largely filled-up Lyman lines in the prototype polar AM Herculis during its high states. It also confirms the hypotheses (i) that irradiation by cyclotron radiation and other radiation sources is the principle cause for the large heated polar caps surrounding the accretion spots on white dwarfs in polars and (ii) that much of the reprocessed light appears in the far ultraviolet and not in the soft X-ray regime as suggested in the original simple theories. We also briefly discuss the role played by hard X-rays in heating the polar cap.