Year: 2025
Type: article
Abstract: ABSTRACT W Ursa Majoris-type contact binary systems (CBs) with period–luminosity (PL) relations are valuable distance indicators. The PL relations of CBs are affected by metallicity. Here, we establish PL relations and period–luminosity–metallicity (PLZ) relations in nine bands from optical to mid-infrared ($BP$, G, $RP$, J, H, $K_S$, $W1$, $W2$, and $W3$) and in five Wesenheit bands based on Gaia Data Release 3 parallaxes. The dispersion of PLZ relations gradually decreases from the optical to mid-infrared bands, with the minimum dispersion of 0.138 mag. We fit the best PL relations for three bands ($W1$, $W_{G,BP,RP}$, and $W_{W1,BP,RP}$) under different parallax uncertainty criteria and determine a parallax (after correction) zero-point of ${\rm zp}_\varpi =24\pm 4$ $\mu$as. After fixing the parallax zero-point, we find that the total zero errors of the PL and PLZ relations are smallest when the parallax uncertainty is less than 2 per cent, resulting in a calibrated CB luminosity with an accuracy of 0.33 per cent, which is more accurate than the classical Cepheids. Furthermore, by examining the absolute magnitude residuals in different metallicity intervals, we find that the use of a linear metallicity effect is appropriate for CBs with different metallicities. These results indicate that CBs are excellent standard candles.
Authors: Jing Li, Xiaodian Chen, Shu Wang, Kun Wang, Kai Li, Licai Deng
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,046
Funders: European Space Agency, National Natural Science Foundation of China, Chinese Academy of Sciences, Youth Innovation Promotion Association of the Chinese Academy of Sciences, National Development and Reform Commission, National Key Research and Development Program of China, Youth Innovation Promotion Association, National Astronomical Observatories, Chinese Academy of Sciences
OpenAlex ID: W6921980957