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arXiv 2103.01884astro-ph.HEastro-ph.SR
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Roche瓣溢出和引力波辐射对中子星-白矮星双星轨道演化的影响

Orbital Evolution of Neutron-Star -- White-Dwarf Binaries by Roche-Lobe Overflow and Gravitational Wave Radiation

Shenghua Yu, Youjun Lu, C. Simon Jeffery

摘要:

我们研究了质量转移和引力波(GW)辐射对接触中子星白矮星(NS-WD)双星轨道演化的影响,以及空间GW探测器(例如,激光干涉仪空间天线,LISA;太极;天琴)。当WD分量充满其洛希瓣时,NS-WD双星成为接触双星,对于质量为0.05-1.4 Msun的WD,GW频率范围为0.0023 - 0.72 Hz。我们发现,一些高质量的NS-WD双星可能会经历不稳定的质量转移后直接合并。然而,大多数NS-WD双星可以避免直接合并,因为接触后的质量转移可以导致轨道演化的逆转。我们的模型可以很好地解释超紧凑X射线源4U 1820- 30的轨道演化。对于4U 1820- 30的4年观测,GW特征应变的预期信噪比(SNR)为~11.0/10.4/2.2(LISA/Taiji/Tianqin)。NS-WD双星GW频率的演化依赖于WD质量。质量大于4U 1820- 30的NS-WD双星预计将以显着更大的SNR检测。对于(1.4+0.5)Msun的NS-WD双星,一周观测的信噪比约为27/40/28(LISA/Taiji/Tianqin)。对于质量为(1.4+>~1.1)Msun的NS-WD双星,可以测量到GW频率和振幅的显著变化,从而有可能确定双星的演化阶段。在距离银河系边缘(~100 kpc)的地方,高质量的NS-WD双星仍然可以在SNR>~1的情况下被探测到。

英文摘要:

We investigate the effects of mass transfer and gravitational wave (GW) radiation on the orbital evolution of contact neutron-star-white-dwarf (NS-WD) binaries, and the detectability of these binaries by space GW detectors (e.g., Laser Interferometer Space Antenna, LISA; Taiji; Tianqin). A NS-WD binary becomes contact when the WD component fills its Roche lobe, at which the GW frequency ranges from ~0.0023 to 0.72 Hz for WD with masses ~0.05-1.4 Msun. We find that some high-mass NS-WD binaries may undergo direct coalescence after unstable mass transfer. However, the majority of NS-WD binaries can avoid direct coalescence because mass transfer after contact can lead to a reversal of the orbital evolution. Our model can well interpret the orbital evolution of the ultra-compact X-ray source 4U 1820--30. For a 4-year observation of 4U 1820--30, the expected signal-to-noise-ratio (SNR) in GW characteristic strain is ~11.0/10.4/2.2 (LISA/Taiji/Tianqin). The evolution of GW frequencies of NS-WD binaries depends on the WD masses. NS-WD binaries with masses larger than 4U 1820--30 are expected to be detected with significantly larger SNRs. For a (1.4+0.5) Msun NS-WD binary close to contact, the expected SNR for a one week observation is ~27/40/28 (LISA/Taiji/Tianqin). For NS-WD binaries with masses of (1.4+>~1.1) Msun, the significant change of GW frequencies and amplitudes can be measured, and thus it is possible to determine the binary evolution stage. At distances up to the edge of the Galaxy (~100 kpc), high-mass NS-WD binaries will be still detectable with SNR>~1.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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