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arXiv · 2501.10613

Optical Flares Detected on a Contact Binary: The First Photometric and Spectroscopic Analysis of a Long-period Low Mass Ratio Contact Binary HAT 307-0007476

Ling-Zhi Li·Kai Li·Xiang Gao·Xiao-Dian Chen·Shuai Feng·Dong-Yang Gao·Di-Fu Guo·Xu Chen·Xing Gao·Guo-You Sun·Shahidin Yaqup·Chunhai Bai·Ali Esamdin
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Abstract

This paper presents the photometric and spectroscopic analysis of a long-period totally eclipsing contact binary (HAT 307-0007476) for the first time. This system is a low mass ratio ($q\sim0.114$) and medium contact binary ($f\sim37.1\%$). Two flare events were detected in multiple bands observations in December 2022. The interval between the two flare events is 4 days. The average duration of these two flares is about 2289s. Both the two flares achieve the energy levels of superflares. The excess emission of the H$_\alpha$ line in the LAMOST spectra of this object was analyzed, indicating its chromospheric activity. The $O-C$ diagram showed a long-term orbital period increase, which is due to the mass transfer between the two component stars. We conclude that HAT 307-0007476 is currently in a stable region based on both $J_{spin}/J_{orb}$ and the comparison between the instability parameters and its current values.

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Ling-Zhi Li, Kai Li, Xiang Gao, Xiao-Dian Chen, Shuai Feng, Dong-Yang Gao, Di-Fu Guo, Xu Chen, Xing Gao, Guo-You Sun, Shahidin Yaqup, Chunhai Bai, Ali Esamdin. 2025-01-18. Optical Flares Detected on a Contact Binary: The First Photometric and Spectroscopic Analysis of a Long-period Low Mass Ratio Contact Binary HAT 307-0007476. https://arxiv.org/abs/2501.10613

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