Terminating a common envelope jets supernova impostor event with a super-Eddington blue supergiant

TL;DR

This study uses one-dimensional stellar simulations to model blue supergiants with low envelopes and super-Eddington luminosity, proposing a new possible end stage for common envelope jets supernova impostor events lasting several years.

Contribution

It introduces a model for the final phase of CEJSN-impostor events, showing how a blue supergiant can form and persist after a jet-powered transient, expanding the understanding of related stellar phenomena.

Findings

Blue supergiant models with low envelope mass and super-Eddington luminosity are feasible.

Such models can last for several years, matching transient event timescales.

The energy from accretion-driven jets can produce these blue supergiants at the end of a CEJSN-impostor.

Abstract

We conducted one-dimensional stellar evolutionary numerical simulations to build blue supergiant stellar models with a very low-envelope mass and a super-Eddington luminosity of 10^7Lo that mimic the last phase of a common envelope evolution (CEE) where a neutron star (NS) accretes mass from the envelope and launches jets that power the system. Common envelope jets supernovae (CEJSNe) are CEE transient events where a NS spirals-in inside the envelope and then the core of a red supergiant (RSG) star accretes mass and launches jets that power the transient event. In case that the NS (or black hole) does not enter the core of the RSG the event is a CEJSN-impostor. We propose that in some cases a CEJSN-impostor event might end with such a phase of a blue supergiant lasting for several years to few tens of years. The radius of the blue supergiant is about tens to few hundreds solar radii. We use a simple prescription to deposit the jets energy into the envelope. We find that the expected accretion rate of envelope mass onto the NS at the end of the CEE allows the power of the jets to be as we assume, 10^7Lo. Such a low-mass envelope might be the end of the RSG envelope, or might be a rebuilt envelope from mass fallback. Our study of a blue supergiant at the termination of a CEJSN-impostor event adds to the rich variety of transients that CEJSNe and CEJSN-impostors might form.