A common envelope jets supernova (CEJSN) impostor scenario for fast blue optical transients

TL;DR

This paper proposes a new polar CEJSN impostor scenario involving a neutron star interacting with a red supergiant, explaining fast blue optical transients like AT2018cow through jet-powered explosions during common envelope evolution.

Contribution

It introduces a novel four-phase model of a CEJSN impostor involving jet activity and circumstellar interactions to explain FBOTs, linking them to progenitors of NS-NS mergers.

Findings

The scenario accounts for the fast timescale of FBOTs due to large-distance jet interactions.

It links FBOTs to the evolutionary path of neutron star and red supergiant systems.

Proposes that many FBOTs are impostors related to common envelope jets supernovae.

Abstract

I propose a new scenario, the polar common envelope jets supernova (CEJSN) impostor scenario, to account for AT2018cow-like fast blue optical transients (FBOTs). The polar CEJSN impostor scenario evolves through four main phases. (1) A red supergiant (RSG) star expands to tidally interact with a neutron star (NS) companion (or a black hole). The interaction increases the RSG mass loss rate to form a circumstellar matter (CSM) halo to ~0.1pc. (2) Shortly before the onset of a common envelope evolution (CEE) and about a year before explosion the NS accretes mass from the RSG envelope and launches jets that inflate two opposite lobes in the CSM within ~100AU. (3) The NS-RSG system enters a CEE phase during which the system ejects most of the envelope mass in a dense equatorial outflow. (4) At the termination of the CEE the leftover envelope forms a circumbinary disk around the NS-core system. The NS accretes mass from the circumbinary disk and launches energetic jets that when collide with the fronts of the CSM lobes power an FBOT event. The low mass of the jets-lobes interaction zones and their large distance, of about 100AU, from the center account for the fast transient. In the future the core collapses to form a second NS. In the far future the two NS might merge. I suggest that FBOTs and similar fast transients are CEJSN impostors which compose a large fraction of the progenitors of NS-NS merger binaries.