Abstract We show that the explosive transition of the neutron star (NS) to a quark star (QS) (a Quark Nova) in Cassiopeia A (Cas A) a few days following the supernova (SN) proper can account for several of the puzzling kinematic and nucleosynthetic features that are observed. The observed decoupling between Fe and 44Ti and the lack of Fe emission within 44Ti regions is expected in the QN model owing to the spallation of the inner SN ejecta by relativistic QN neutrons. Our model predicts the 44Ti to be more prominent to the NW of the central compact object (CCO) than in the SE and little of it along the NE-SW jets, in agreement with NuStar observations. Other intriguing features of Cas A are addressed, such as the lack of a pulsar wind nebula and the reported few percent drop in the CCO temperature over a period of 10 yr.
Keywords ISM: individual object (Cassiopeia A) — ISM: supernova remnants — stars: neutron
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