WOCS 4540: Detailed Analysis of a Very Long Orbital Period Blue Straggler

Abstract

WOCS 4540 is the longest orbital period ($P_{\mathrm{orb}}=3030$ days) blue straggler (BSS) - white dwarf (WD) pair in the old open cluster NGC 188 . It also contains one of the most luminous BSS in the cluster. Prior \textit{Hubble Space Telescope} COS spectroscopy measured a WD mass of 0.53 $M_{\odot }$, indicative of a carbon-oxygen WD and suggesting previous mass transfer from an asymptotic branch giant (AGB). Detailed modeling of the system evolution, including red giant branch phase wind mass transfer, AGB wind Roche-lobe overflow and regular Roche-lobe overflow, is done with Modules for Experiments in Stellar Astrophysics. The best-fit model produces excellent agreement with a wide array of observational constraints on the BSS, the WD and the binary system. To produce the observed luminosity and effective temperature of the BSS, all three donor mass-transfer mechanisms contribute similarly to build a 1.5 $M_{\odot }$ BSS. The overall mass-transfer efficiency is 55%. Regular Roche-lobe overflow occurs only during the largest AGB thermal pulse, but yields a very high accretion rate at 75% efficiency and briefly (less than 1 Myr) a very high luminosity boost from the accretor.

arXiv comment17 pages, 17 figures, accepted for publication in ApJ

References in corpus (37)

• Modules for Experiments in Stellar Astrophysics (MESA)
• Modules for Experiments in Stellar Astrophysics (MESA): Giant Planets, Oscillations, Rotation, and Massive Stars
• Modules for Experiments in Stellar Astrophysics (MESA): Binaries, Pulsations, and Explosions
• Modules for Experiments in Stellar Astrophysics (MESA): Convective Boundaries, Element Diffusion, and Massive Star Explosions
• Modules for Experiments in Stellar Astrophysics (MESA): Pulsating Variable Stars, Rotation, Convective Boundaries, and Energy Conservation
• The rotation rates of massive stars: the role of binary interaction through tides, mass transfer and mergers
• Asteroseismology of old open clusters with Kepler: direct estimate of the integrated RGB mass loss in NGC6791 and NGC6819
• On the triple origin of blue stragglers
• The initial-final mass relationship of white dwarfs revisited: effect on the luminosity function and mass distribution
• Mergers and Obliquities in Stellar Triples
• Wind Roche-lobe overflow: Application to carbon-enhanced metal-poor stars
• A Binary Origin for Blue Stragglers in Globular Clusters
• A Chemical Abundance Study of 10 Open Clusters Based on WIYN-Hydra Spectroscopy
• WIYN Open Cluster Study XXXII: Stellar Radial Velocities in the Old Open Cluster NGC 188
• 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
• An Analytic Technique for Constraining the Dynamical Origins of Multiple Star Systems Containing Merger Products
• Implications for the Formation of Blue Straggler Stars from HST Ultraviolet Observations of NGC 188
• Age and distance for the old open cluster NGC188 from the eclipsing binary member V12
• A new, Gaia based, catalogue of blue straggler stars in open clusters
• Detection of white dwarf companions to blue stragglers in the open cluster NGC 188: direct evidence for recent mass transfer
• Evolution of accretor stars in massive binaries: broader implications from modeling ζ Ophiuchi
• Mergers of close primordial binaries
• The blue stragglers formed via mass transfer in old open clusters
• The Distribution of Collisionally Induced Blue Stragglers in the Colour-Magnitude Diagram
• WIYN Open Cluster Study. XXXVI. Spectroscopic Binary Orbits in NGC 188
• Effects of chemical composition and thermohaline mixing on the accreting components for low--mass close binaries: application to blue stragglers
• A Census of Blue Stragglers in Gaia DR2 Open Clusters as a Test of Population Synthesis and Mass Transfer Physics
• Constraining Mass Transfer Histories of Blue Straggler Stars with COS Spectroscopy of White Dwarf Companions
• Observations of Spin-Down in Post-Mast-Transfer Stars and the Possibility for Blue Straggler Gyrochronology
• Massive binary star mergers in galactic nuclei: implications for blue stragglers, binary S-stars and gravitational waves
• How much mass and angular momentum can the progenitors of carbon-enriched stars accrete?
• WOCS 5379: Detailed Analysis of the Evolution of a Post-Mass-Transfer Blue Straggler
• Bayesian Investigation of Isochrone Consistency Using the Old Open Cluster NGC 188
• Mergers of Equal-Mass Binaries with Compact Object Companions from Mass Transfer in Triple Star Systems
• A Triple Origin for Twin Blue Stragglers in Close Binaries
• Lithium and mass loss in massive AGB stars in the Large Magellanic Clouds

Cited by in corpus (3)

• Blue Stragglers and Friends: Initial Evolutionary Pathways in Close Low-Mass Binaries: Literature Review
• The Blue Lurker WOCS 14020: A Long-Period Post-Common-Envelope Binary in M67 Originating from a Merger in a Triple System
• Unveiling Bifurcated Blue Straggler Sequences in NGC 2173: Insights from Binary Evolution