2024/11/25 by Jason S. Alexander, Michael D. Albrow, Alexander, Jason +1
Chemistry · Materials Science · #Astrophysics of Galaxies (astro-ph.GA) #Crystal Structures and Properties #FOS: Physical sciences #Inorganic Chemistry and Materials #Inorganic Fluorides and Related Compounds #Solar and Stellar Astrophysics (astro-ph.SR)
paper · pdf · doi:10.48550/arxiv.2411.16089
openalex publication_date 2024/11/25 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We apply probabilistic generative modelling of colour-magnitude diagrams to six young Galactic open star clusters and determine their mass functions, binary mass-ratio distributions, and the frequencies of binary stars. We find that younger clusters tend to exhibit a higher incidence of binaries than their older counterparts. The mass-ratio distribution is fairly flat for the clusters with one exception that exhibits a sharp increase for q\gtrsim0.9. The ratio of the number of cluster binaries for which q>0.75 to the number of binaries for which q>0.5 (referred to as FQ75) ranges from ∼0.4 - 0.8. This metric increases with the binary-star frequency of a cluster, but declines with cluster age. This may be due to non-ionizing 3-body dynamical processing of a primordial population of close binaries with initial mass ratios, q ≃ 1.