The double helium-white dwarf channel for the formation of AM CVn binaries
The double helium-white dwarf channel for the formation of AM CVn binaries
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AM CVn 双星形成的氦-白矮星双通道
DOI：
10.1088/1674-4527/18/1/9
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发表时间：
2018
影响因子：
1.8
通讯作者：
Bi Shao-Lan
中科院分区：
文献类型：
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作者：
Zhang Xian-Fei;Liu Jin-Zhong;Jeffery C. Simon;Hall Philip D.;Bi Shao-Lan
由于引力波辐射的轨道衰变，大多数距离很近的双氦白色矮星将在哈勃时间内合并。然而，具有低质量比的显著部分将由于稳定的质量传递而存活很长时间。两个氦白色矮星（HeWD）之间的这种稳定的质量转移为AM CVn双星的产生提供了一个通道。在之前对双HeWD祖细胞的计算中，吸积的HeWD被视为点质量。我们已经计算了16双HeWD模型的演变，以调查详细治疗两个组件的演变的后果。我们发现，具有稳定和不稳定的质量传递的二进制文件之间的边界略有修改，这种方法。通过与观测周期和质量比的比较，我们利用双HeWDs通道重新测定了8颗已知的AM CVn型恒星的质量，它们是HM Cnc，AM CVn，V406 Hya，J 0926，J1240，GP Com，Gaia 14 aae和V396 Hya。GP Com和V396 Hya的N/C/O表面丰度比可以用稳定的HeWD双通道来解释。从我们的计算中得到的质量估计用于讨论在激光干涉仪空间天线（丽莎）项目的背景下预测的引力波信号。
Most close double helium white dwarfs will merge within a Hubble time due to orbital decay by gravitational wave radiation. However, a significant fraction with low mass ratios will survive for a long time as a consequence of stable mass transfer. Such stable mass transfer between two helium white dwarfs (HeWDs) provides one channel for the production of AM CVn binary stars. In previous calculations of double HeWD progenitors, the accreting HeWD was treated as a point mass. We have computed the evolution of 16 double HeWD models in order to investigate the consequences of treating the evolution of both components in detail. We find that the boundary between binaries having stable and unstable mass transfer is slightly modified by this approach. By comparing with observed periods and mass ratios, we redetermine masses of eight known AM CVn stars by our double HeWDs channel, i.e. HM Cnc, AM CVn, V406 Hya, J0926, J1240, GP Com, Gaia14aae and V396 Hya.We propose that central spikes in the triple-peaked emission spectra of J1240, GP Com and V396 Hya and the surface abundance ratios of N/C/O in GP Com can be explained by the stable double HeWD channel. The mass estimates derived from our calculations are used to discuss the predicted gravitational wave signal in the context of the Laser Interferometer Space Antenna (LISA) project.