Unresolved Binaries in the Intermediate Mass Range in the Pleiades Star Cluster

• Published in: arXiv.org 2022-01
• Main Authors: Malofeeva, A, Seleznev, A, Carraro, G
• Format: Article
• Language: English
• Subjects: Binary stars; Mass ratios; Star clusters; Stellar populations
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2201.05146

The identification of binary stars of different mass ratios in resolved stellar populations is a challenging task. We show how the photometric diagram constructed with the pseudo-colors (H-W2)-W1 vs W2-(BP-K) can be employed to estimate the binary and multiple star ratios and the distribution of their component mass ratio \(q\) effectively. As an application, we investigate the Pleiades star cluster in the range of primary component mass between 0.5 and 1.8 \(M_{\odot}\). The binary star ratio is found to be between 0.54\(\pm\)0.11 and 0.70\(\pm\)0.14. On the other hand, the ratio of systems with multiplicity more than 2 is between 0.10\(\pm\)0.00 and 0.14\(\pm\)0.01. The distribution of the component mass ratio \(q\) has been approximated by a power law with the exponent between -0.53\(\pm\)0.10 and -0.63\(\pm\)0.22. Below 0.5 \(M_{\odot}\), we expect a large number of brown dwarfs among secondary components.