A Super-Eddington Wind Scenario for the Progenitors of Type Ia Supernovae

TL;DR

This paper uses advanced stellar simulations to propose a super-Eddington wind mechanism that regulates mass accretion on white dwarfs, offering new insights into the progenitors of Type Ia supernovae, especially in low-metallicity environments.

Contribution

It introduces a super-Eddington wind scenario that occurs at lower accretion rates than previously thought, providing an alternative to existing wind models for Type Ia supernova progenitors.

Findings

Super-Eddington wind prevents white dwarfs from becoming red giants at high accretion rates.

The wind mechanism operates effectively even in low-metallicity environments.

Simulations show similar properties to steady-state models but with critical differences in wind triggering.

Abstract

The accretion of hydrogen-rich material onto carbon-oxygen white dwarfs (CO WDs) is crucial for understanding type Ia supernova (SN Ia) from the single-degenerate model, but this process has not been well understood due to the numerical difficulties in treating H and He flashes during the accretion. For the CO WD masses from 0.5 to $1.378\,{M}_\odot$ and accretion rates in the range from $10^{-8}$ to $10^{-5}\,{M}_\odot\,\mbox{yr}^{-1}$, we simulated the accretion of solar-composition material onto CO WDs using the state-of-the-art stellar evolution code of {\sc MESA}. For comparison with the steady-state models (e.g \citet{nskh07}), we firstly ignored the contribution from nuclear burning to the luminosity when determining the Eddington accretion rate and found that the properties of H burning in our accreting CO WD models are similar to those from the steady-state models, except that the critical accretion rates at which the WDs turn into red giants or H-shell flashes occur on their surfaces are slightly higher than those from the steady-state models. However, the super-Eddington wind is triggered at much lower accretion rates, than previously thought, when the contribution of nuclear burning to the total luminosity is included. This super-Eddington wind naturally prevents the CO WDs with high accretion rates from becoming red giants, thus presenting an alternative to the optically thick wind proposed by \cite{hkn96}. Furthermore, the super-Eddington wind works in low-metallicity environments, which may explain SNe Ia observed at high redshifts.