The importance of the remnant's mass for VLTP born again times. Implications for V4334 Sgr and V605 Aql

TL;DR

This study uses numerical simulations to show how remnant mass influences the timescales of born again events in stars like V4334 Sgr and V605 Aql, explaining observed rapid outbursts.

Contribution

It demonstrates that remnant mass critically determines the born again timescales in VLTP scenarios, aligning models with observed phenomena.

Findings

Lower mass remnants evolve in a few years.

Higher mass remnants (>0.6 M☉) have longer, ~100-year timescales.

Remnant mass explains the diversity in born again events.

Abstract

We present numerical simulations of the very late thermal pulse (VLTP) scenario for a wide range of remnant masses. We show that, by taking into account the different possible remnant masses, the fast outburst evolution of V4334 Sgr (a.k.a. Sakurai's Object) and V605 Aql can be reproduced within standard 1D stellar evolution models. A dichotomy in the born again timescales is found, with lower mass remnants evolving in a few years and higher mass remnants (M $\hbox{\rlap{\hbox{\lower4pt\hbox{$\sim$}}}\hbox{$>$}}$ 0.6 M$_{\odot}$) failing to expand due to the H-flash and, as a consequence, evolving in timescales typical of He-shell flash driven born agains ($\sim 100$ yr).