论文标题
Be+剥离的星星二进制的X射线排放
The X-ray emission of Be+stripped star binaries
论文作者
论文摘要
利用Chandra，Swift和XMM-Newton的观察结果，我们研究了所有已知的BE+SDO系统的高能特性，以及7个额外的Be Binaries怀疑是避开了脱落的恒星。发现观察到的X射线特性与其他BE样品观察到的特性相似。这些系统中的绝大多数（25个中的15个）表现出非常微弱（和柔软的）X射线发射，另外六个肯定不是明亮的X射线源。只有两个系统显示γ-CAS特性（即明亮和硬X射线），其中一个是一个新的检测：HD37202（Zeta Tau）。由于高温和高吸收（可能是由于其高倾斜度）的组合，它具有极其硬的光谱。同时，可能会注意到，近年来，先前报道的该恒星的循环行为消失了。取而代之的是，对于HALPHA线，观察到较短的周期和对称线轮廓。最近有人提出，在γ-CAS恒星中观察到的奇特的X射线排放可能是由于Be Star的磁盘与其热，脱衣舞的伴侣的风之间的碰撞引起的。该样品中的γ-CAS类似物的一小部分以及伽马 - CAS病例的已知伴侣的特性（低质量或不太热，与预测相反），结合了实际的Star-Star and Colliding-Wind经验知识，使磁盘 - 束缚碰撞不可能解释gamma-cas femomemenonon femomenon femomemenonon。
Using observations from Chandra, Swift and XMM-Newton, we investigate the high-energy properties of all known (18) Be+sdO systems as well as 7 additional Be binaries suspected to harbour stripped stars. The observed X-ray properties are found to be similar to those observed for other Be samples. The vast majority of these systems (15 out of 25) display very faint (and soft) X-ray emission, and six others are certainly not bright X-ray sources. Only two systems display gamma-Cas characteristics (i.e. bright and hard X-rays), and one of them is a new detection: HD37202 (zeta Tau). It presents an extremely hard spectrum, due to a combination of high temperature and high absorption (possibly due to its high inclination). In parallel, it may be noted that the previously reported cyclic behaviour of this Be star has disappeared in recent years. Instead, shorter cycles and symmetric line profiles are observed for the Halpha line. It had been recently suggested that the peculiar X-ray emissions observed in gamma-Cas stars could arise from a collision between the disk of a Be star and the wind of its hot, stripped-star companion. The small fraction of gamma-Cas analogs in this sample, as well as the properties of the known companions of the gamma-Cas cases (low mass or not extremely hot, contrary to predictions), combined to the actual stripped-star and colliding-wind empirical knowledge, make the disk-wind collision an unlikely scenario to explain the gamma-Cas phenomenon.
