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

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).