The response of a red supergiant to a common envelope jets supernova (CEJSN) impostor event

Abstract

ABSTRACT Using a 1D stellar evolution code, we simulate the response of a red supergiant (RSG) star to injection of energy and to mass removal. We take the values of the energy that we inject and the mass that we remove according to our previous 3D hydrodynamical simulations of a neutron star (NS) on a highly eccentric orbit that enters the envelope of an RSG star for half a year and launches jets as it accretes mass via an accretion disc. We find that for injected energies of $\simeq 10^{47} {--} 10^{48} {~\rm erg}$ and removed mass of $\simeq 0.03{--}0.6\, {\rm M}_\odot$ the RSG envelope expands to a large radius. Therefore, we expect the NS to continue to orbit inside this massive inflated envelope for several more months, up to about twice the initial RSG radius, to continue to accrete mass and launch jets for a prolonged period. Although these late jets are weaker than the jets that the NS launches while inside the original RSG envelope, the late jets might actually be more influential on the light curve, leading to a long, several months to few years, and bright, about $\gtrsim10^8\, {\rm L}_\odot$, transient event. The RSG returns to more or less a relaxed structure after about 10 yr, and so another transient event might occur in the next periastron passage of the NS. Our results add to the already rich variety of jet-driven explosions/outbursts that might account for many puzzling transient events.