Common envelope jets supernova (CEJSN) impostors resulting from a neutron star companion

TL;DR

This paper introduces a new class of transient outbursts caused by neutron stars interacting with evolved massive stars, launching jets that produce high-velocity ejecta without resulting in a supernova, potentially explaining certain luminous transients.

Contribution

It proposes the concept of CEJSN impostors and describes their characteristics, origins, and possible role in stellar evolution and transient phenomena.

Findings

Ejecta velocities can reach 10,000 km/s without a supernova.

Transient durations are weeks to months with energies up to 1 foe.

Neutron star interactions may be key in the evolution of NS-NS binary progenitors.

Abstract

We propose a new type of repeating transient outburst initiated by a neutron star (NS) entering the envelope of an evolved massive star, accreting envelope material and subsequently launching jets which interact with their surroundings. This interaction is the result of either a rapid expansion of the primary star due to an instability in its core near the end of its nuclear evolution, or due to a dynamical process which rapidly brings the NS into the primary star. The ejecta can reach velocities of 10,000 km/s despite not being a supernova, and might explain such velocities in the 2011 outburst of the luminous blue variable progenitor of SN 2009ip. The typical transient duration and kinetic energy are weeks to months, and up to approximately 1 foe, respectively. The interaction of a NS with a giant envelope might be a phase in the evolution of the progenitors of most NS-NS binary systems that later undergo a merger event. If the NS spirals in all the way to the core of the primary star and brings about its complete disruption we term this a `common envelope jets supernova' (CEJSN), which is a possible explanation for the peculiar supernova iPTF14hls. For a limited interaction of the NS with the envelope we get a less luminous transient, which we term a CEJSN impostor.