2020/10/16 by Andrei Tokovinin, Andreï Tokovinin, M. G. Petr-Gotzens +3
Mathematics · Physics and Astronomy · #Astro and Planetary Science #Astrometry #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Binary number #Mathematics #Molecular cloud #Open cluster #Orion Nebula #Physics #Population #Stars #Stellar classification #Stellar, planetary, and galactic studies #astro-ph.GA #astro-ph.SR
paper · pdf · doi:10.3847/1538-3881/abc2d6
published as 2020, AJ, 160, 268 · Accepted for publicaion in The Astronomical Journal. 19 pages, 22 figures, 7 tables
arxiv created 2020/10/16 · openalex publication_date 2020/11/18 · arxiv updated 2021/01/11 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Abstract Statistics of low-mass pre-main-sequence binaries in the Orion OB1 association with separations ranging from 0.″6 to 20″ (220 to 7400 au at 370 pc) are studied using images from the VISTA Orion mini survey and astrometry from Gaia. The input sample based on the CVSO catalog contains 1137 stars of K and M spectral types (masses between 0.3 and 0.9 ), 1021 of which are considered to be association members. There are 135 physical binary companions to these stars with mass ratios above ∼0.13. The average companion fraction is 0.09 ± 0.01 over 1.2 decades in separation, slightly less than, but still consistent with, the field. We found a difference between the Ori OB1a and OB1b groups, the latter being richer in binaries by a factor of 1.6 ± 0.3. No overall dependence of the wide-binary frequency on the observed underlying stellar density is found, although in the Ori OB1a off-cloud population, these binaries seem to avoid dense clusters. The multiplicity rates in Ori OB1 and in sparse regions like Taurus differ significantly, hinting that binaries in the field may originate from a mixture of diverse populations.