Contribution of primordial binary evolution to the two blue-straggler sequences in globular cluster M30

Abstract

Two blue-straggler sequences discovered in globular cluster M30 provide a strong constraint on the formation mechanisms of blue stragglers. We study the formation of the blue-straggler binaries through binary evolution, and find that binary evolution can contribute to the blue stragglers in both of the sequences. Whether a blue straggler is located in the blue sequence or red sequence depends on the contribution of the mass donor to the total luminosity of the binary, which is generally observed as a single star in globular clusters. The blue stragglers in the blue sequence have a cool white-dwarf companion, while the majority ($\sim 60\%$) of the objects in the red sequence are the binaries that are still experiencing mass transfer, but there are also some objects that the donors have just finished the mass transfer (the stripped-core stars, $\sim 10\%$) or the blue stragglers (the accretors) have evolved away from the blue sequence ($\sim 30\%$). Meanwhile, W UMa contact binaries found in both sequences may be explained by various mass ratios, that is, W UMa contact binaries in the red sequence have two components with comparable masses (e.g. mass ratio $q\sim$ 0.3-1.0), while those in the blue sequence have low mass ratio (e.g. $q<$ 0.3). However, the fraction of blue sequence in M30 cannot be reproduced by binary population synthesis if we assumed the initial parameters of a binary sample to be the same as that of the field. This possible indicates that dynamical effects on binary systems is very important in globular clusters.

27 pages, 9 figures, accepted for publication in ApJ

References in corpus (49)

• Evolution of binary stars and the effect of tides on binary populations
• Comprehensive analytic formulae for stellar evolution as a function of mass and metallicity
• Approximate input physics for stellar modelling
• The ACS Survey of Galactic Globular Clusters. XII. Photometric Binaries along the Main-Sequence
• On the effects of dynamical evolution on the initial mass function of globular clusters
• Dynamical age differences among coeval star clusters as revealed by blue stragglers
• The Evolution of Binary Fractions in Globular Clusters
• A Complete Survey of Case A Binary Evolution with Comparison to Observed Algol-Type Systems
• Two distinct sequences of blue straggler stars in the globular cluster M30
• Efficiency of mass transfer in massive close binaries, Tests from double-lined eclipsing binaries in the SMC
• Relative Frequencies of Blue Stragglers in Galactic Globular Clusters: Constraints for the Formation Mechanisms
• Discovery of Carbon/Oxygen depleted Blue Straggler Stars in 47 Tucanae: the chemical signature of a mass-transfer formation process
• Mass transfer from a giant star to a main sequence companion and its contribution to long-orbital-period blue stragglers
• A mass transfer origin for blue stragglers in NGC 188 as revealed by half-solar-mass companions
• Contact Binaries of the Galactic Disk: Comparison of the Baade's Window and Open Cluster Samples
• The Evolution of Cool Algols
• Interacting Binaries with Eccentric Orbits. Secular Orbital Evolution Due To Conservative Mass Transfer
• Double Blue Straggler sequences in GCs: the case of NGC 362
• W UMa-type Binary Stars in Globular Clusters
• Discovery of another peculiar radial distribution of Blue Stragglers in Globular Clusters: The case of 47 Tuc
• ON BLUE STRAGGLER FORMATION BY DIRECT COLLISIONS OF MAIN-SEQUENCE STARS
• Interacting Binaries with Eccentric Orbits II. Secular Orbital Evolution Due To Non-Conservative Mass Transfer
• Implications for the Formation of Blue Straggler Stars from HST Ultraviolet Observations of NGC 188
• Detection of white dwarf companions to blue stragglers in the open cluster NGC 188: direct evidence for recent mass transfer
• Blue Stragglers After the Main Sequence
• The blue stragglers formed via mass transfer in old open clusters
• The evolutionary status of W Ursae Majoris-type systems
• Evolution of stellar collision products in open clusters. I. Blue stragglers in N-body models of M67
• The Origins of Blue Stragglers and Binarity in Globular Clusters
• Interacting Binaries with Eccentric Orbits. III. Orbital Evolution due to Direct Impact and Self-Accretion
• High-resolution simulations of stellar collisions between equal-mass main-sequence stars in globular clusters
• Primordial Binary Evolution and Blue Stragglers
• The Distribution of Collisionally Induced Blue Stragglers in the Colour-Magnitude Diagram
• Binary coalescence from case A evolution -- mergers and blue stragglers
• Contact binary stars of the W UMa type as distance tracers
• Effects of chemical composition and thermohaline mixing on the accreting components for low--mass close binaries: application to blue stragglers
• Wide-Field CCD Photometry of the Globular Cluster M30
• The Clusters AgeS Experiment (CASE). II. The Eclipsing Blue Straggler OGLEGC-228 in the Globular Cluster 47 Tuc
• The Blue Straggler Star Population in NGC 1261: Evidence for a Post-Core-Collapse Bounce State
• The Formation Rate of Blue Stragglers in 47 Tucanae
• FLAMES and XSHOOTER spectroscopy along the two BSS sequences of M30
• The binary mass transfer origin of the red blue straggler sequence in M30
• Blue Straggler Stars in Galactic Open Clusters and the Simple Stellar Population Model
• The detached-binary channel for the formation of contact binaries
• The energy transfer and its effects on the secondaries in W Ursae Majoris-type contact binaries
• Photometric study of the variable star population in the globular cluster NGC 6397
• Binary interactions as a possible scenario for the formation of multiple stellar populations in globular clusters
• Model computations of blue stragglers and W UMa-type stars in globular clusters
• The effect of stellar evolution upon Population II Contact Binaries in the Period-Color Relation. I. Equal-Mass, Marginal Contact Systems

Cited by in corpus (13)

• The "dynamical clock": dating the internal dynamical evolution of star clusters with Blue Straggler Stars
• Fast rotating Blue Stragglers prefer loose clusters
• Detection of a White Dwarf companion to a Blue Straggler Star in the outskirts of globular cluster NGC 5466 with the Ultraviolet Imaging Telescope (UVIT)
• Discovery of a double sequence of blue straggler stars in the core-collapsed globular cluster NGC 6256
• Discovery of a double Blue Straggler sequence in M15: new insight into the core-collapse process
• The double Blue Straggler sequence in NGC2173: a field contamination artefact
• The origin of the two populations of blue stragglers in M30
• Case AD, AR, and AS binary evolution and their possible connections with W UMa binaries
• Discovery of double BSS sequences in the old Galactic open cluster Berkeley 17
• The Rich Lack Close Neighbours: The Dependence of Blue-Straggler Fraction on Metallicity
• Rotational velocities of Blue Straggler Stars in the Globular Cluster M55
• Mass transfer of low-mass binaries and chemical anomalies among unevolved stars in globular clusters
• Unveiling Bifurcated Blue Straggler Sequences in NGC 2173: Insights from Binary Evolution