Recently, a single-line spectroscopic binary, LTD064402+245919, has been discovered by Yang et al. Using data from LAMOST and ZTF, the unseen companion is estimated to have a mass of 1-3 M⊙, orbiting a subgiant with orbital period of 14.50 days, making it a good compact binary candidate without X-ray emission. However, new light curves from ZTF and ASAS-SN, have shown the depth of one dip increases towards a bluer wavelength, indicating LTD064402+245919 is more likely to be a subgiant with a red star. Using both Wilson-Devinney code and Phoebe, the derived Teff of secondary is about 3400 K, corresponding to a red M2/3 star. Additionally, the 20% error of parallax from Gaia is large. The mass of subgiant will be 1.28 M⊙ instead of 2.77 M⊙, if the refined distance of 5.0kpc is used. Nevertheless, new multi-colour photometry are warranted for the final confirmation of binary properties.
@article{arxiv.2205.15916,
title = {LTD064402+245919, compact binary or subgiant with red star eclipsing binary?},
author = {Jincheng Guo and Cheng Liu},
journal= {arXiv preprint arXiv:2205.15916},
year = {2022}
}