The evolution of accretor stars in binary systems due to accretion of increasingly helium-rich material

Abstract

The recent discovery of examples of intermediate-mass helium stars have offered new insights into interacting binaries. These observations will allow significant improvements in our understanding of helium stars. However, in the creation of these stars their companions may accrete a significant amount of helium-rich stellar material. These creates stars with unusual composition profiles -- stars with helium-rich cores, hydrogen-rich lower envelopes and a helium-rich outer envelope. Thus the mean molecular weight reaches a minimum in the the middle of the star rather than continuously decreasing outwards in mass. To demonstrate this structure we present Cambridge STARS model calculations of an example interacting binary systems where the helium-rich material is transferred, and compare it to one where the composition of the accreted mass is fixed to the companion's surface composition. We show that the helium-rich material leads to the accretor being 0.2 dex hotter and 0.15 dex more luminous than models where the composition is not helium rich. We use a simple BPASS v2.2 population model to estimate that helium-rich mass transfer occurs in 23 per cent of massive binaries that undergo mass transfer. This suggests this is a common process. This binary process has implications for the discrepancy between spectroscopic and gravitational masses of stars, the production of ionizing photons and possibly the modelling of high redshift galaxies.

Accepted for publication in MNRAS

References in corpus (66)

• On the variation of the Initial Mass Function
• 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
• Evolution of binary stars and the effect of tides on binary populations
• Mass-loss predictions for O and B stars as a function of metallicity
• Grids of stellar models with rotation - I. Models from 0.8 to 120 Msun at solar metallicity (Z = 0.014)
• Mind your Ps and Qs: the Interrelation between Period (P) and Mass-ratio (Q) Distributions of Binary Stars
• Pre-Supernova Evolution of Massive Single and Binary Stars
• Binary Population and Spectral Synthesis Version 2.1: construction, observational verification and new results
• Reevaluating Old Stellar Populations
• The rotation rates of massive stars: the role of binary interaction through tides, mass transfer and mergers
• Observed Fractions of Core-Collapse Supernova Types and Initial Masses of their Single and Binary Progenitor Stars
• V1309 Scorpii: merger of a contact binary
• Stellar Population Effects on the Inferred Photon Density at Reionization
• Thermohaline mixing: A physical mechanism governing the photospheric composition of low-mass giants
• The death of massive stars - II. Observational constraints on the progenitors of type Ibc supernovae
• Theoretical uncertainties of the type Ia supernova rate
• Formation of contact in massive close binaries
• Runaway stars as progenitors of supernovae and gamma-ray bursts
• The origin of spin in binary black holes: Predicting the distributions of the main observables of Advanced LIGO
• Binary star progenitors of long gamma-ray bursts
• The spin of the second-born black hole in coalescing binary black holes
• The VLT-FLAMES survey of massive stars: rotation and nitrogen enrichment as the key to understanding massive star evolution
• Spectral models for binary products: Unifying Subdwarfs and Wolf-Rayet stars as a sequence of stripped-envelope stars
• BONNSAI: a Bayesian tool for comparing stars with stellar evolution models
• Efficiency of mass transfer in massive close binaries, Tests from double-lined eclipsing binaries in the SMC
• Different to the core: the pre-supernova structures of massive single and binary-stripped stars
• It has to be cool: on supergiant progenitors of binary black hole mergers from common-envelope evolution
• On the consistent treatment of the quasi-hydrostatic layers in hot star atmospheres
• Ionizing spectra of stars that lose their envelope through interaction with a binary companion: role of metallicity
• POSYDON: A General-Purpose Population Synthesis Code with Detailed Binary-Evolution Simulations
• Modelling the binary progenitor of supernova 1993J
• V1309 SCO - Understanding a merger
• Emission-line diagnostics of nearby HII regions including interacting binary populations
• The R136 star cluster dissected with Hubble Space Telescope/STIS. II. Physical properties of the most massive stars in R136
• New Insights into the Evolution of Massive Stars and Their Effects on Our Understanding of Early Galaxies
• Massive stars at low metallicity: Evolution and surface abundances of O dwarfs in the SMC
• The disappearance of the helium-giant progenitor of the type Ib supernova iPTF13bvn and constraints on its companion
• The Physical Properties and Effective Temperature Scale of O-type Stars as a Function of Metallicity. III. More Results from the Magellanic Clouds
• Spectroscopic and physical parameters of Galactic O-type stars. III. Mass discrepancy and rotational mixing
• Detailed models of interacting short-period massive binary stars
• The VLT-FLAMES Tarantula Survey XIX. B-type Supergiants - Atmospheric parameters and nitrogen abundances to investigate the role of binarity and the width of the main sequence
• SN 2011hw: Helium-Rich Circumstellar Gas and the Luminous Blue Variable to Wolf-Rayet Transition in Supernova Progenitors
• Evolution of accretor stars in massive binaries: broader implications from modeling ζ Ophiuchi
• The spins of compact objects born from helium stars in binary systems
• Effects of rotational mixing on the asteroseismic properties of solar-type stars
• Stellar population of the superbubble N206 in the LMC II. Parameters of the OB and WR stars, and the total massive star feedback
• A Bake-Off Between CMFGEN and FASTWIND: Modeling the Physical Properties of SMC and LMC O-type Stars
• Pre-supernova evolution and final fate of stellar mergers and accretors of binary mass transfer
• Thermohaline Mixing and its Role in the Evolution of Carbon and Nitrogen Abundances in Globular Cluster Red Giants: The Test Case of Messier 3
• Rejuvenated accretors have less bound envelopes: Impact of Roche lobe overflow on subsequent common envelope events
• Effects of chemical composition and thermohaline mixing on the accreting components for low--mass close binaries: application to blue stragglers
• The effect of the 19F(alpha,p)22Ne reaction rate uncertainty on the yield of fluorine from Wolf-Rayet Stars
• Mass transfer in eccentric binary systems using the binary evolution code BINSTAR
• Explosions of blue supergiants from binary mergers for SN 1987A
• Does simultaneous solution matter for stellar evolution codes?
• Evaluating chemically homogeneous evolution in stellar binaries: Electromagnetic implications -- Ionizing photons, SLSN-I, GRB, Ic-BL
• Extreme isolation of WN3/O3 stars and implications for their evolutionary origin as the elusive stripped binaries
• The Asteroseismic Imprints of Mass Transfer: A Case Study of a Binary Mass Gainer in the SPB Instability Strip
• The eclipsing binary systems with $\delta$ Scuti component. I. KIC 10661783
• Reverse Algols and hydrogen-rich Wolf-Rayet stars from very massive binaries
• Characterizing Observed Extra Mixing Trends in Red Giants using the Reduced Density Ratio from Thermohaline Models
• End-to-end study of the home and genealogy of the first binary neutron star merger
• On the evolutionary nature of puffed-up stripped star binaries and their occurrence in stellar populations
• Constraints on the Binarity of the WN3/O3 Class of Wolf-Rayet Stars
• Carbon-enhanced metal-poor stars and thermohaline mixing

Cited by in corpus (3)

• Binarity at LOw Metallicity (BLOeM): massive star variability revealed using a novel software tool for point-spread function fitting of TESS images
• The effect of near-core mixing on rejuvenation and the asteroseismic properties of massive accretors
• Kinematics of Wolf-Rayet Stars in the LMC: Clues to Subtype Origins