2016/09/08 by Zhenxin Lei, Gang Zhao, Aihua Zeng +4
Physics and Astronomy · #Astro and Planetary Science #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Atomic physics #Binary star #Blue straggler #Globular cluster #Helium #Horizontal branch #Mass ratio #Metallicity #Physics #Stars #Stellar, planetary, and galactic studies #astro-ph.SR
paper · pdf · doi:10.1093/mnras/stw2242
12 pages, 11 figures, 2 tables, accepted for publication in MNRAS
openalex publication_date 2016/09/08 · openalex created_date 2016/09/16 · arxiv created 2016/09/29 · arxiv updated 2016/10/05 · openalex updated_date 2026/08/05
Employing tidally enhanced stellar wind, we studied in binaries the effects of metallicity, mass ratio of primary to secondary, tidal enhancement efficiency and helium abundance on the formation of blue hook (BHk) stars in globular clusters (GCs). A total of 28 sets of binary models combined with different input parameters are studied. For each set of binary model, we presented a range of initial orbital periods that is needed to produce BHk stars in binaries. All the binary models could produce BHk stars within different range of initial orbital periods. We also compared our results with the observation in the Teff–logg diagram of GC NGC 2808 and ω Cen. Most of the BHk stars in these two GCs locate well in the region predicted by our theoretical models, especially when C/N-enhanced model atmospheres are considered. We found that mass ratio of primary to secondary and tidal enhancement efficiency have little effects on the formation of BHk stars in binaries, while metallicity and helium abundance would play important roles, especially for helium abundance. Specifically, with helium abundance increasing in binary models, the space range of initial orbital periods needed to produce BHk stars becomes obviously wider, regardless of other input parameters adopted. Our results were discussed with recent observations and other theoretical models.