The puzzling early detection of low velocity 56Ni decay lines in SN 2014J: Hints of a compact remnant

TL;DR

This paper proposes a Quark-Nova Ia model to explain early low-velocity 56Ni decay lines in SN 2014J, involving a neutron star to quark star transition and a compact remnant affecting the explosion dynamics.

Contribution

It introduces a novel model involving a quark star remnant to explain early spectral features and light-curve behavior in Type Ia supernova SN 2014J.

Findings

Low-velocity 56Ni lines detected earlier than expected.

The model fits the observed light-curve including early rise.

Predictions for observational tests of the model.

Abstract

We show that the low-velocity 56Ni decay lines detected earlier than expected in the type Ia SN 2014J find an explanation in the Quark-Nova Ia model which involves the thermonuclear explosion of a tidally disrupted sub-Chandrasekhar White Dwarf in a tight Neutron-Star-White-Dwarf binary system. The explosion is triggered by impact from the Quark-Nova ejecta on the WD material; the Quark-Nova is the explosive transition of the Neutron star to a Quark star triggered by accretion from a CO torus (the circularized WD material). The presence of a compact remnant (the Quark Star) provides: (i) an additional energy source (spin-down power) which allows us to fit the observed light-curve including the steep early rise; (ii) a central gravitational potential which slows down some of the 56Ni produced to velocities of a few 1000 km/s. In our model, the 56Ni decay lines become optically visible at ~20 days from explosion time in agreement with observations. We list predictions that can provide important tests for our model.