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arXiv · 2504.18202

A post-common-envelope binary with double-peaked Balmer emission lines from TMTS

Qichun Liu·Xiaofeng Wang·Jie Lin·Chengyuan Wu·Chunqian Li·V. Alexei Filippenko·G. Thomas Brink·Yi Yang·Weikang Zheng·Cheng Liu·Cuiying Song·Mikhail Kovalev·Hongwei Ge·Fenghui Zhang·Xiaobin Zhang·Qiqi Xia·Haowei Peng·Gaobo Xi·Jun Mo·Shengyu Yan·Jianrong Shi·Jiangdan Li·Tuan Yi
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Abstract

The dynamical method provides an efficient way to discover post-common-envelope binaries (PCEB) with faint white dwarfs (WDs), thanks to the development of time-domain survey projects. We perform a comprehensive analysis of the PCEB system TMTS J15530469+4457458 (J1553), discovered by the Tsinghua University-Ma Huateng Telescopes for Survey, to explore its physical origin and evolutionary fate. This system is characterized by double-peaked Balmer emission lines, and a cross-correlation function is applied to derive its radial velocity (RV) from a series of phase-resolved Keck spectra. Analyses with the cross-correlation function suggest that this system is a single-lined spectroscopic binary and only one star is optically visible. Further analysis through Doppler tomography indicates that J1553 is a detached binary without an accretion disk. Under such a configuration, the simultaneous light-curve and RV fitting reveal that this system contains an unseen WD with mass $M_{\rm A}=0.56\pm 0.09\, M_{\odot}$, and an M4 dwarf with mass $M_{\rm B}=0.37\pm 0.02\,M_{\odot}$ and radius $R_{\rm B}=0.403^{+0.014}_{-0.015}\,R_{\odot}$. The extra prominent Balmer emission lines seen in the spectra can trace the motion of the WD, which are likely formed near the WD surface as a result of wind accretion. According to the MESA simulation, J1553 could have evolved from a binary consisting of a 2.0-4.0 ${M}_{\odot}$ zero-age-main-sequence star and an M dwarf with an initial orbital period $P_i\approx 201-476$ d, and the system has undergone a common-envelope (CE) phase. After about $3.3\times10^6$ yr, J1553 should evolve into a cataclysmic variable, with a transient state as a supersoft X-ray source at the beginning. J1553 is an excellent system for studying wind accretion, CE ejection physics, and binary evolution theory.

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Qichun Liu, Xiaofeng Wang, Jie Lin, Chengyuan Wu, Chunqian Li, V. Alexei Filippenko, G. Thomas Brink, Yi Yang, Weikang Zheng, Cheng Liu, Cuiying Song, Mikhail Kovalev, Hongwei Ge, Fenghui Zhang, Xiaobin Zhang, Qiqi Xia, Haowei Peng, Gaobo Xi, Jun Mo, Shengyu Yan, Jianrong Shi, Jiangdan Li, Tuan Yi. 2025-06-07. A post-common-envelope binary with double-peaked Balmer emission lines from TMTS. https://doi.org/10.1051/0004-6361%2F202553732

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