We consider stable mass transfer from the secondary to the primary of an extreme mass ratio binary system. We show that when the mass transfer is sufficiently fast, mass leakage occurs through the outer Lagrange point L2, in addition to the usual transfer through L1. We provide an analytical estimate for the mass leakage rate through L2 and find the conditions in which it is comparable to the mass transfer rate through L1. Focusing on a binary system of a main-sequence star and a super-massive black hole, driven by the emission of gravitational radiation, we show that it may sustain stable mass transfer, along with mass loss through L2. If such a mass-transferring system occurs at our Galactic Centre, it produces a gravitational wave signal detectable by future detectors, such as eLISA. The signal evolves according to the star's adiabatic index and cooling time. For low mass stars, the evolution is faster than the Kelvin-Helmholtz cooling rate driving the star out of the main-sequence. In some cases, the frequency and amplitude of the signal may both decrease with time, contrary to the standard chirp of a coalescing binary. Mass loss through L2, when occurs, decreases the evolution timescale of the emitted gravitational wave signal by up to a few tens of per cent. We conclude that L2 mass ejection is a crucial factor in analyzing gravitational waves signals produced by such systems.
Co-evolution of Nuclear Star Clusters and Massive Black Holes: Extreme Mass-Ratio Inspirals
Guangzhou University（广州大学）；Key Laboratory for Astronomical Observation and Technology of Guangzhou（广州市天文观测与技术重点实验室）；Astronomy Science and Technology Research Laboratory of Department of Education of Guangdong Province（广东省教育厅天文科学与技术研究实验室）；Universitat Politècnica de València（瓦伦西亚理工大学）；Max-Planck-Institute for Extraterrestrial Physics（马克斯·普朗克地外物理研究所）
A positive period derivative in the quasi-periodic eruptions of ZTF19acnskyy
Massachusetts Institute of Technology（麻省理工学院）；Black Hole Initiative at Harvard University（哈佛大学黑洞倡议）；Columbia University（哥伦比亚大学）；New York University（纽约大学）；Centro de Astrobiología (CAB), CSIC-INTA（西班牙国家航空航天技术研究所与西班牙国家科学研究委员会天体生物学中心）；Universidad Adolfo Ibáñez（阿道夫·伊巴涅斯大学）；Millennium Nucleus on Transversal Research and Technology to Explore Supermassive Black Holes (TITANS)（探索超大质量黑洞跨学科研究与技术千年核）；Instituto de Estudios Astrofísicos（天体物理研究所）
Tidal capture and repeating partial tidal disruption events of giant stars
Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education（现代天文与天体物理教育部重点实验室）；School of Astronomy and Space Science, Nanjing University（南京大学天文与空间科学学院）
Simulations of the tidal interaction and mass transfer of a star in an eccentric orbit around an intermediate-mass black hole: the case of HLX-1
螺旋星系ESO 243-49附近的X射线源HLX-1是目前最好的中等质量黑洞候选者。它的最大热辐射光度为$10^{42}$ erg s $^{-1}$，这意味着它的质量流入率为$\sim10^{-4}$ MSun yr $^{-1}$，但这个质量的来源尚不清楚。有人提出，有一颗恒星在围绕黑洞的偏心轨道上，在近心点转移质量。为了研究这个系统的轨道演化，我们进行恒星演化模拟使用台面和SPH模拟的恒星轨道周围的一个中等质量的黑洞使用FI。我们使用amuse框架运行并耦合这些模拟。我们发现，质量损失通过第一和第二拉格朗日点，有一个延迟的近心点通道和峰值质量损失事件之间的时间长达10天。我们在模拟中发现的轨道演化时间尺度比分析模型预测的要大，但这些模型落在我们结果的误差范围内。尽管轨道演化很快，但我们无法重现观测到的爆发期变化。我们的结论是，在恒星轨道的变化与系统参数的研究在这里是无法解释所有观察到的功能HLX-1。
