Type Ia Supernovae from wide white-dwarfs triples

Erez Michaely

Published 2020-09-16Version 1

For ultra-wide systems (with outer orbit >$10^{3}{\rm AU})$ the galactic field is collisional. Hence, ultra-wide triple white-dwarfs (TWDs) can be perturbed, by flyby stars, to sufficiently high outer eccentricity such that the triple becomes dynamically unstable. An unstable triple undergoes multiple binary-single resonant encounters between all three WDs. These encounters might result in a direct collision between any random two WDs and lead to a Type Ia supernova (SN) event. In case where the multiple resonant encounters did not produce a collision a compact binary is formed (while the third WD is ejected), this binary either collides or merges via gravitational wave emission, similar to the classic double-degenerate (DD) channel. In this research study we estimate the galactic rates of Type Ia SN from this channel to be $4\%-46\%$ and an addition of $1\%-10\%$ to the DD scenario.