The impact of wind accretion in Evolving Symbiotic Systems

TL;DR

This study examines how geometric corrections to wind accretion models affect the evolution of symbiotic binary systems, highlighting the importance of improved models for accurate predictions of white dwarf growth and supernova progenitors.

Contribution

The paper introduces an improved wind accretion model that incorporates geometric corrections, demonstrating its impact on the evolution of symbiotic systems compared to traditional models.

Findings

Modified model does not reach Chandrasekhar limit, implying different supernova progenitor pathways.

Standard BHL model predicts white dwarf growth to Chandrasekhar limit in compact systems.

Revised model aligns with observed symbiotic systems and captures accretion regime transitions.

Abstract

We investigate the impact of geometric corrections to the Bondi-Hoyle-Lyttleton (BHL) accretion scheme applied to evolving symbiotic systems. We model systems where 0.7 and 1 M$_\odot$ white dwarfs accrete material from Solar-like stars with initial masses of 1, 2, and 3 M$_\odot$. The primary star is evolved using the MESA stellar evolution code, while the orbital dynamics of the system are calculated using REBOUND. The analysis focuses on systems evolving through the red giant branch and the thermally-pulsating asymptotic giant branch phases that do not experience a Wind Roche Lobe Overflow phase. We compare three scenarios: no accretion, standard BHL accretion, and the improved wind accretion. The choice of accretion prescription critically influences the evolution of symbiotic systems. Simulations using the modified model did not reach the Chandrasekhar limit, suggesting that type Ia supernova progenitors require accretors originating from ultra-massive WDs. In contrast, the standard BHL model predicts WD growth to this limit in compact systems. This discrepancy suggests that population synthesis studies adopting the traditional BHL approach may yield inaccurate results. The revised model successfully reproduces the accretion properties of observed symbiotic systems and predicts transitions between different accretion regimes driven by donor mass-loss variability. These results emphasize the need for updated wind accretion models to accurately describe the evolution of symbiotic binaries.