Evolutionary modelling of subdwarf B stars using MESA with the predictive mixing and convective premixing schemes

Abstract

Results of evolutionary modelling of subdwarf B stars are presented. For the first time, we explore the core and near-core mixing in the subdwarf B stars using new algorithms available in the MESA code: the predictive mixing scheme and the convective premixing scheme. We show how both methods handle the problems with determination of convective boundary, discrepancy between core masses obtained from asteroseismology and evolutionary models, and long-standing problems related to the core-helium-burning phase such as splitting of the convective core and the occurrence of breathing pulses. We find that the convective premixing scheme is the preferable algorithm. The masses of the convective core in case of the predictive mixing and the combined convective and semiconvective regions in case of the convective premixing scheme are higher than in the models with only the Ledoux criterion, but they are still lower than the seismic-derived values. Both algorithms are promising and alternative methods of studying models of subdwarf B stars.

16 pages, 14 figures, accepted for publication in MNRAS

References in corpus (24)

• The NumPy array: a structure for efficient numerical computation
• Modules for Experiments in Stellar Astrophysics (MESA)
• Modules for Experiments in Stellar Astrophysics (MESA): Pulsating Variable Stars, Rotation, Convective Boundaries, and Energy Conservation
• Updated Electron-Conduction Opacities: The Impact on Low-Mass Stellar Models
• Probing the properties of convective cores through g modes: high-order g modes in SPB and gamma Doradus stars
• Angular momentum transport by heat-driven g-modes in slowly pulsating B stars
• Coulomb tunneling for fusion reactions in dense matter: Path integral Monte Carlo versus mean field
• Modeling He-rich subdwarfs through the hot-flasher Scenario
• The dependence of convective core overshooting on stellar mass: semi-empirical determination using the diffusive approach with two different element mixtures
• On the proper use of the Schwarzschild and Ledoux criteria in stellar evolution computations
• Structural glitches near the cores of red giants revealed by oscillations in g-mode period spacings from stellar models
• Asteroseismology revealing trapped modes in KIC 10553698A
• Statistical errors and systematic biases in the calibration of the convective core overshooting with eclipsing binaries. A case study: TZ Fornacis
• Subdwarf B stars from the common envelope ejection channel
• The treatment of mixing in core helium burning models -- III. Suppressing core breathing pulses with a new constraint on overshoot
• The core helium flash revisited: I. One and two-dimensional hydrodynamic simulations
• KIC 1718290: A Helium-rich V1093-Her-like Pulsator on the Blue Horizontal Branch
• A few StePS forward in unveiling the complexity of galaxy evolution: light-weighted stellar ages of intermediate redshift galaxies with WEAVE
• The blue-edge problem of the V1093 Her instability strip revisited using evolutionary models with atomic diffusion
• The effects of near-core convective shells on the gravity modes of the subdwarf B pulsator KIC 10553698A
• Three new pulsating sdB stars discovered with SuperWASP
• Asteroseismic signatures of the helium-core flash
• Revising the evolutionary stage of HD 163899: the effects of convective overshooting and rotation
• Binaries among Extreme Horizontal Branch Stars in Globular Clusters