A Common Envelope Jets Supernova (CEJSN) Impostor Scenario for Fast Blue Optical Transients

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 r similar or equal to 0.1 pc. (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 approximate to 100 au. (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 colliding 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 100 au, 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 NSs 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.

Automated summary

This paper proposes the polar common envelope jets supernova (CEJSN) impostor scenario to account for fast blue optical transients (FBOTs) like AT2018cow. The scenario involves four main phases: the interaction between a red supergiant and a neutron star, mass accretion, common envelope evolution, and the formation of a circumbinary disk. The interaction between jets and lobes explains the fast transient phenomenon.