Entering the Wind Roche Lobe Overflow realm in Symbiotic Systems

Abstract

We present a suite of dynamical simulations designed to explore the orbital and accretion properties of compact (2$-$7 AU) symbiotic systems, focusing on wind accretion, drag forces, and tidal interactions. Using three levels of physical complexity, we model systems of accreting white dwarfs (WDs) with masses of 0.7, 1.0, and 1.2 M${}_{\odot }$ orbiting evolving Solar-like stars with 1, 2, and 3 M${}_{\odot }$. We show that systems alternate between standard wind accretion and Wind Roche Lobe Overflow (WRLO) regimes during periods of high mass-loss rate experienced by the donor star (the peak of red giant phase and/or thermal pulses). For some configurations, the standard wind accretion has mass accretion efficiencies similar to those obtained by WRLO regime. Tidal forces play a key role in compact systems, leading to orbital shrinkage and enhanced accretion efficiency. We find that systems with high-mass WDs ($\ge 1$ M${}_{\odot }$) and massive donors (2$-$3 M${}_{\odot }$) are the only ones to reach the Chandrasekhar limit. Interestingly, the majority of our simulations reach the Roche lobe overflow condition that is not further simulated given the need of more complex hydrodynamical simulations. Our analysis shows that increasing physical realism, by including drag and tides, systematically leads to more compact final orbital configurations. Comparison with compact known symbiotic systems seems to suggest that they are very likely experiencing orbital decay produced by tidal forces.

14 pages; 9 figures; 2 tables; accepted in MNRAS

References in corpus (9)

• Modules for Experiments in Stellar Astrophysics (MESA)
• Distant future of the Sun and Earth revisited
• Binary stars in the Galactic thick disc
• Orbital eccentricities of binary systems with a former AGB star
• Interacting Binaries with Eccentric Orbits II. Secular Orbital Evolution Due To Non-Conservative Mass Transfer
• Wind mass transfer in S-type symbiotic binaries I. Focusing by the wind compression model
• T CrB: overview of the accretion history, Roche-lobe filling, orbital solution, and radiative modeling
• Testing tidal theory using Gaia binaries: the red giant branch
• Outflow dynamics of dust-driven wind models and implications for cool envelopes of PNe