Issue |
A&A
Volume 693, January 2025
|
|
---|---|---|
Article Number | A322 | |
Number of page(s) | 11 | |
Section | Stellar structure and evolution | |
DOI | https://doi.org/10.1051/0004-6361/202451415 | |
Published online | 29 January 2025 |
LAMOST J171013+532646: A detached short-period noneclipsing hot subdwarf + white dwarf binary
1
Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100101, China
2
Yunnan Observatories, Chinese Academy of Sciences, Kunming 650011, China
3
School of Astronomy and Space Science, University of Chinese Academy of Sciences, Beijing 100049, China
4
International Centre of Supernovae, Yunnan Key Laboratory, Kunming 650216, People’s Republic of China
5
Department of Astronomy, Xiamen University, Xiamen Fujian 361005, China,
⋆ Corresponding authors; yuanhl@bao.ac.cn; htzhang@bao.ac.cn
Received:
7
July
2024
Accepted:
28
November
2024
We present an analysis of LAMOST J171013.211+532646.04 (hereafter J1710), a binary system comprising a hot subdwarf B star (sdB) and a white dwarf (WD) companion. Multi-epoch spectroscopy revealed an orbital period of 109.20279 minutes, consistent with TESS and ZTF photometric data. This means that this is the sixth detached system known to harbor a WD companion with a period shorter than two hours. J1710 is remarkably close to Earth. It is situated at a distance of only 350.68−4.21+4.20 pc, with a Gaia G-band magnitude of 12.59. This renders it conducive for continuous observations. The spectral temperature is around 25 164 K, in agreement with fitting results (25301−743+839 K) based on a spectral energy distribution. The TESS light curve displays ellipsoidal variation and Doppler beaming without eclipsing features. Through fitting the TESS light curve using the Wilson-Devinney code, we determined the masses for the sdB (M1= 0.44−0.07+0.06 M⊙) and the compact object (M2= 0.54−0.07+0.10 M⊙); the compact object likely is a WD. Furthermore, MESA models suggest that the sdB, with a helium core mass of 0.431 M⊙ and a hydrogen envelope mass of 1.3 × 10−3 M⊙, is in the early helium main-sequence phase. The MESA binary evolution shows that the J1710 system is expected to evolve into a double WD system. This means that it is an important source of low-frequency gravitational waves.
Key words: binaries: general / subdwarfs / white dwarfs
© The Authors 2025
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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