2015ApJ...801...64O

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 (WD) in a tight neutron-star-WD binary system. The explosion is triggered by impact from the quark-nova (QN) ejecta on the WD material; the QN is the explosive transition of the neutron star to a quark star (QS) triggered by accretion from a CO torus (the circularized WD material). The presence of a compact remnant (the QS) provides: (1) an additional energy source (spin-down power) which allows us to fit the observed light-curve including the steep early rise; (2) a central gravitational potential which slows down some of the ⁵⁶Ni produced to velocities of a few 10³ 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.