论文标题
调查缺乏大型恒星的主要序列伴侣
Investigating the lack of main-sequence companions to massive Be stars
论文作者
论文摘要
大约20％的B型星是经典的恒星。这种现象与快速旋转密切相关，其起源仍不清楚。它可以植根于单二极星进化。在二进制通道的框架内，最初更大的恒星将质量和角动量转移到了原始的次级，这成为恒星。然后，该系统与二进制相关的二进制伴侣演变为二进制，后来可能会在超新星事件中破坏。因此，如果二进制通道主导着恒星的形成，那么人们可能会严重缺乏与主序列（MS）伴侣的二进制文件。通过对银河系早期型的幅度限制样本的文献进行广泛的明星评论，我们研究是否已知是否存在MS伴侣的二进制物。我们的样本是由BESS数据库构建的，并与所有恒星的所有可用文献进行了交叉匹配。在505个恒星的初始列表中，我们比v <= 12 mag的B1.5提早编制了287个银河为星星的最终样本。在这些中，有13个物体被报道为已知的MS伴侣，有11个作为二进制物，是未知，不确定或辩论的同伴。我们没有发现与MS同伴的二进制文件的确认报告。对于其余的263个目标，文献中没有重要的多样性报告，这意味着它们要么是具有微弱伴侣的二进制物，要么是真正的单身。明显缺乏报道的MS伴侣是恒星，与检测到的B+B MS二进制群的数量大量相反，它强烈支持以下假设：早期型为恒星是二元相互作用产物，它们是在质量和伴侣恒星中的角度动量转移后旋转的二元相互作用产物。以面值为单位，我们的结果可能表明，大多数早期型是通过二进制质量转移形成的恒星。
About 20% of all B-type stars are classical Be stars. The Be phenomenon is strongly correlated with rapid rotation, the origin of which remains unclear. It may be rooted in single- or binary-star evolution. In the framework of the binary channel, the initially more massive star transfers mass and angular momentum to the original secondary, which becomes a Be star. The system then evolves into a Be binary with a post-main-sequence companion, which may later be disrupted in a supernova event. Hence, if the binary channel dominates the formation of Be stars, one may expect a strong lack of close Be binaries with main sequence (MS) companions. Through an extensive, star-by-star review of the literature of a magnitude-limited sample of Galactic early-type Be stars, we investigate whether Be binaries with MS companions are known to exist. Our sample is constructed from the BeSS database and cross-matched with all available literature on the individual stars. Out of an initial list of 505 Be stars, we compile a final sample of 287 Galactic Be stars earlier than B1.5 with V<=12 mag. Out of those, 13 objects were reported as Be binaries with known post-MS companions and 11 as binaries with unknown, uncertain or debated companions. We find no confirmed reports of Be binaries with MS companions. For the remaining 263 targets, no significant reports of multiplicity exist in the literature, implying that they are either Be binaries with faint companions, or truly single. The clear lack of reported MS companions to Be stars, which stands in contrast to the high number of detected B+B MS binaries, strongly supports the hypothesis that early-type Be stars are binary interaction products that spun up after mass and angular momentum transfer from a companion star. Taken at face value, our results may suggest that a large majority of the early-type Be stars have formed through binary mass-transfer.
