Issue |
A&A
Volume 692, December 2024
|
|
---|---|---|
Article Number | L4 | |
Number of page(s) | 7 | |
Section | Letters to the Editor | |
DOI | https://doi.org/10.1051/0004-6361/202451947 | |
Published online | 04 December 2024 |
Letter to the Editor
Detection of the lowest mass ratio contact binary in the universe: TYC 3801-1529-1
1
Shandong Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, School of Space Science and Technology, Institute of Space Sciences, Shandong University, Weihai, Shandong 264209, China
2
Yunnan Observatories, Chinese Academy of Sciences, Kunming 650216, China
3
Department of Astronomy and Space Science, Chungbuk National University, Cheongju 361-763, Korea
⋆ Corresponding author; kaili@sdu.edu.cn
Received:
21
August
2024
Accepted:
9
November
2024
This paper presents the first analysis of the contact binary TYC 3801-1529-1. We observed four sets of multiple bands complete light curves and one set of radial velocity curve of the primary component. Based on a simultaneous investigation of our observed and TESS light curves and the radial velocity curve, we found that TYC 3801-1529-1 is an extremely low-mass-ratio, medium contact binary with q = 0.0356, with the contribution of the third light at a level of about 10%. Its mass ratio is lower than V1187 Her, making TYC 3801-1529-1 the lowest mass-ratio contact binary ever found in the universe. The light curves observed in 2022 are asymmetric, which is aptly explained by a hot spot on the primary component. A 16-year eclipse timings analysis indicates a secular increase orbital period with a rate of dp/dt = 7.96(±0.35)×10−7 d yr−1. We studied the stability of this target and identified that not only the value of Jspin/Jorb, but also the mass ratio surpass the unstable boundary. Hence, TYC 3801-1529-1 presents a challenge to theoretical research and ought to be considered a progenitor of a contact binary merger.
Key words: binaries: close / binaries: eclipsing / stars: evolution / stars: individual: TYC 3801-1529-1
© The Authors 2024
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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