The Local Group Symbiotic Star Population and its Weak Relation with Type Ia Supernovae

TL;DR

This study estimates the population of symbiotic stars in the Local Group and assesses their potential role as progenitors of Type Ia supernovae, finding they are unlikely to be the main source.

Contribution

It provides the first empirical and statistical estimates of symbiotic star populations across Local Group galaxies and evaluates their connection to Type Ia supernovae.

Findings

Symbiotic stars are much less common in dwarf galaxies than in the Milky Way.

Only about 0.5-8% of Type Ia supernovae in the Milky Way may originate from symbiotic progenitors.

Symbiotic stars are unlikely to be the dominant progenitors of Type Ia supernovae.

Abstract

Here we study the symbiotic stars (SySt) population and its relation with type Ia supernovae (SNe Ia) in the galaxies of the Local Group. SySt are low- and/or intermediate-mass evolved binary systems where a white dwarf (WD) accretes mass from a giant star. A fraction of these WDs can become massive enough to reach the Chandrasekhar mass. Therefore, SySt have been considered as potential SNe Ia progenitors. Taking two approaches, one empirical and another statistical, we estimated the SySt population on the Galaxy as having a minimum value of $1.69\times10^3$ and a expected one of $3.23\times10^4$. For Local Group dwarfs galaxies, the computed SySt population ranges from 2 to 4 orders of magnitudes lower. Concerning the SNe Ia with SySt progenitors, our general result is that SySt are not the main SNe Ia progenitors. On the other hand, we still expect that about 0.5-8% of the SNe Ia have symbiotic progenitors in the Milky Way, while the majority of the - low-mass - dwarfs galaxies did not experience a symbiotic type Ia supernova.