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| Format: | Preprint |
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2026
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| Online Access: | https://arxiv.org/abs/2606.01867 |
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| _version_ | 1866917553684611072 |
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| author | Chen, Y. H. Yu, Y. Han, Z. |
| author_facet | Chen, Y. H. Yu, Y. Han, Z. |
| contents | LAMOST J010103.13+275449.6 is a bright star with an apparent magnitude of 10.764 in the g band. We have obtained the LAMOST Low Resolution Spectrum, the Gaia XP spectrum, the apparent magnitudes from SDSS, 2MASS, and WISE, as well as the light curve from TESS. In the spectroscopic study, the detected He I lines trace high temperature features and the detected Ca I, Na I lines trace low temperature features. The multi-band apparent magnitudes and color indices also exhibit characteristics that do not match those of a normal single F8 type star. Most interestingly, we find that the light curve's variability period gradually decreases from 1.7216\,d to 0.8444\,d. We conduct binary fitting investigations on this source using Binary Tools, MESA, and PHOEBE programs. LAMOST J010103.13+275449.6 should be a binary system consisting of a $\sim$3000\,K, $\sim$0.12\,$M_{\odot}$ star and a $\sim$6000\,K, $\sim$1.2\,$M_{\odot}$ star, with an orbital period of 1.7216\,d and a separation of 6.63\,$R_{\odot}$. The tidal locking of the cool star, along with the magnetic activity on its hemisphere facing the hot star and the opposite hemisphere, can explain the halving of the photometric variability period. For a fully convective M dwarf with a rotation period of about 1.7\,d, strong magnetic activity is frequently observed. This is only a semi-quantitative preliminary fit. More in depth studies can be carried out in the future based on more spectra that may be released by LAMOST. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2606_01867 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | LAMOST J010103.13+275449.6: A New Binary with a Gradually Halving Photometric Variability Period Chen, Y. H. Yu, Y. Han, Z. Solar and Stellar Astrophysics LAMOST J010103.13+275449.6 is a bright star with an apparent magnitude of 10.764 in the g band. We have obtained the LAMOST Low Resolution Spectrum, the Gaia XP spectrum, the apparent magnitudes from SDSS, 2MASS, and WISE, as well as the light curve from TESS. In the spectroscopic study, the detected He I lines trace high temperature features and the detected Ca I, Na I lines trace low temperature features. The multi-band apparent magnitudes and color indices also exhibit characteristics that do not match those of a normal single F8 type star. Most interestingly, we find that the light curve's variability period gradually decreases from 1.7216\,d to 0.8444\,d. We conduct binary fitting investigations on this source using Binary Tools, MESA, and PHOEBE programs. LAMOST J010103.13+275449.6 should be a binary system consisting of a $\sim$3000\,K, $\sim$0.12\,$M_{\odot}$ star and a $\sim$6000\,K, $\sim$1.2\,$M_{\odot}$ star, with an orbital period of 1.7216\,d and a separation of 6.63\,$R_{\odot}$. The tidal locking of the cool star, along with the magnetic activity on its hemisphere facing the hot star and the opposite hemisphere, can explain the halving of the photometric variability period. For a fully convective M dwarf with a rotation period of about 1.7\,d, strong magnetic activity is frequently observed. This is only a semi-quantitative preliminary fit. More in depth studies can be carried out in the future based on more spectra that may be released by LAMOST. |
| title | LAMOST J010103.13+275449.6: A New Binary with a Gradually Halving Photometric Variability Period |
| topic | Solar and Stellar Astrophysics |
| url | https://arxiv.org/abs/2606.01867 |