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arXiv 0804.1215astro-ph
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自旋加速和热点可以将质量从双星中驱出

Spin-up and hot spots can drive mass out of a binary

W. Van Rensbergen, J. P. De Greve, C. De Loore, N. Mennekens

备注：
12 pages, 7 figures, accepted for publication in A&A; accepted version
发表信息：
A&A 487, 1129--1138 (2008)
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摘要：

更新了出生时具有B型原发灶的Algols的周期和质量比的观察分布。保守演化不能产生具有高质量比的大部分：即[0.4-0.6]中的q。因此，相互作用的双星必须在Algolism之前或期间失去质量。在RLOF期间，质量连续地从供体转移到获得者。增益器向上旋转，有时达到临界速度。因此，增益器上的赤道物质较少受系统约束。来自供体的物质通过第一个拉格朗日点猛烈地撞击在供体的表面或吸积盘的边缘，在撞击区域产生热点。旋转能（快速旋转）和辐射能（热点）的总和取决于质量损失率。位于撞击区域的试验质量上的两种能量之和正好等于其在某个临界值处的结合能。只要质量传递速率小于这个值，获得者接受来自供体的所有质量：RLOF保守地发生。但一旦超过临界利率，赢家将获得不超过临界值，RLOF进入自由时代。低质量双星的质量损失率永远不会超过临界值。中等质量的双星演化主要是保守的，但在RLOF点火后不久的快速质量转移的短时期内，质量将从系统中被吹走。质量为9+5.4太阳质量的双星（P在[2-4] d）几乎总是保守地演化。只有在大约20，000年的时间里，获得者才没有能力掌握来自捐赠者的所有材料。在这短暂的时间流逝中，系统的大部分质量被吹到星际空间。质量比箱[0.4-0.6]现在更好地表示。

英文摘要：

The observed distribution of periods and mass ratios of Algols with a B type primary at birth was updated. Conservative evolution fails to produce the large fraction with a high mass ratio: i.e. q in [0.4-0.6]. Interacting binaries thus have to lose mass before or during Algolism. During RLOF mass is transferred continuously from donor to gainer. The gainer spins up; sometimes up to critical velocity. Equatorial material on the gainer is therefore less bound to the system. The material coming from the donor through the first Langrangian point impinges violently on the surface of the gainer or the edge of the accretion disc, creating a hot spot in the area of impact. The sum of rotational energy (fast rotation) and radiative energy (hot spot) depends on the mass-loss rate. The sum of both energies on a test mass located in the impact area equals exactly its binding energy at some critical value. As long as the mass transfer rate is smaller than this value the gainer accepts all the mass coming from the donor: RLOF happens conservatively. But as soon as the critical rate is exceeded the gainer will acquire no more than the critical value and RLOF runs into its liberal era. Low mass binaries never achieve mass-loss rates larger than the critical value. Intermediate mass binaries evolve mainly conservatively but mass will be blown away from the system during the short era of rapid mass transfer soon after RLOF-ignition. Binaries with 9+5.4 solar masses (P in [2-4] d) evolve almost always conservatively. Only during some 20,000 years the gainer is not capable of grasping all the material that comes from the donor. During this short lapse of time a significant fraction of the mass of the system is blown into interstellar space. The mass ratio bin [0.4-0.6] is now much better represented.

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