The Most Luminous Supernova ASASSN-15lh: Signature of a Newborn Rapidly-Rotating Strange Quark Star

TL;DR

This paper proposes that the extremely luminous supernova ASASSN-15lh was powered by a newborn strange quark star with high bulk viscosity, offering a potential signature for the birth of such exotic compact objects.

Contribution

It introduces a novel explanation that a strange quark star's suppressed r-mode instability can account for the supernova's luminosity, distinguishing it from neutron star models.

Findings

Strange quark stars can efficiently power superluminous supernovae.

Gravitational-radiation-driven r-mode instability is suppressed in strange quark stars.

ASASSN-15lh may be a signature of a newborn strange quark star.

Abstract

In this paper we show that the most luminous supernova discovered very recently, ASASSN-15lh, could have been powered by a newborn ultra-strongly-magnetized pulsar, which initially rotates near the Kepler limit. We find that if this pulsar is a neutron star, its rotational energy could be quickly lost as a result of gravitational-radiation-driven r-mode instability; if it is a strange quark star, however, this instability is highly suppressed due to a large bulk viscosity associated with the nonleptonic weak interaction among quarks and thus most of its rotational energy could be extracted to drive ASASSN-15lh. Therefore, we conclude that such an ultra-energetic supernova provides a possible signature for the birth of a strange quark star.