2020/05/04 by Nate Bastian, N. Bastian, Sebastian Kamann +6 · 41 citations
Physics and Astronomy · #Astro and Planetary Science #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Bimodality #Cluster (spacecraft) #Galaxy #Geometry #Luminosity #Main sequence #Open cluster #Physics #Rotation (mathematics) #Star cluster #Stars #Stellar collision #Stellar evolution #Stellar rotation #Stellar, planetary, and galactic studies #astro-ph.GA #astro-ph.SR
paper · pdf · doi:10.1093/mnras/staa1332
published in Monthly Notices of the Royal Astronomical Society 495(2), 1978-1983 (Oxford University Press) · 6 pages, 2 figures, accepted for publication in MNRAS
arxiv created 2020/05/04 · openalex created_date 2020/05/13 · openalex publication_date 2020/05/13 · arxiv updated 2020/05/27 · openalex updated_date 2026/08/06
ABSTRACT We address the origin of the observed bimodal rotational distribution of stars in massive young and intermediate age stellar clusters. This bimodality is seen as split main sequences at young ages and also has been recently directly observed in the Vsini distribution of stars within massive young and intermediate age clusters. Previous models have invoked binary interactions as the origin of this bimodality, although these models are unable to reproduce all of the observational constraints on the problem. Here, we suggest that such a bimodal rotational distribution is set-up early within a cluster’s life, i.e. within the first few Myr. Observations show that the period distribution of low-mass (\lesssim 2 M_\odot) pre-main-sequence (PMS) stars is bimodal in many young open clusters, and we present a series of models to show that if such a bimodality exists for stars on the PMS that it is expected to manifest as a bimodal rotational velocity (at fixed mass/luminosity) on the main sequence for stars with masses in excess of ∼1.5 M⊙. Such a bimodal period distribution of PMS stars may be caused by whether stars have lost (rapid rotators) or been able to retain (slow rotators) their circumstellar discs throughout their PMS lifetimes. We conclude with a series of predictions for observables based on our model.