A possible formation channel for blue hook stars in globular cluster - II. Effects of metallicity, mass ratio, tidal enhancement efficiency and helium abundance

Abstract

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.

12 pages, 11 figures, 2 tables, accepted for publication in MNRAS

References in corpus (15)

• Modules for Experiments in Stellar Astrophysics (MESA)
• The nucleus of the Sagittarius dSph galaxy and M54: a window on the process of galaxy nucleation
• The fraction of second generation stars in Globular Clusters from the analysis of the Horizontal Branch
• Mass loss on the red giant branch: the value and metallicity dependence of Reimers' η in globular clusters
• The core binary fractions of star clusters from realistic simulations
• The Peculiar Horizontal Branch Morphology of the Galactic Globular Clusters NGC 6388 and NGC 6441: new insights from UV observations
• First full evolutionary computation of the He-flash induced mixing in Population II stars
• The metallicity spread and the age-metallicity relation of Omega Centauri
• Helium and Multiple Populations in the Massive Globular Cluster NGC6266 (M62)
• Rapidly rotating second-generation progenitors for the blue hook stars of ω Cen
• The Hottest Horizontal-Branch Stars in omega Centauri - Late Hot Flasher vs. Helium Enrichment
• A Helium-Carbon Correlation on the Extreme Horizontal Branch in $\omega$ Centauri
• The Clusters AgeS Experiment (CASE). I. V209 omega Cen - An Eclipsing Post-Common Envelope Binary in the Globular Cluster omega Cen
• A possible formation channel for blue hook stars in globular cluster
• Binary interactions as a possible scenario for the formation of multiple stellar populations in globular clusters

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