Ultra–High‐Energy Cosmic Rays from Hypothetical Quark Novae

We explore acceleration of ions in the Quark Nova (QN) scenario, where a neutron star experiences an explosive phase transition into a quark star (born in the propeller regime). In this picture, two cosmic ray components are isolated: one related to the randomized pulsar wind and the other to the propelled wind, both boosted by the ultra-relativistic Quark Nova shock. The latter component acquires energies $10^{15} {\rm eV} 10^{18.6}$ eV. The composition is dominated by ions present in the pulsar wind in the energy range above $10^{18.6}$ eV, while at energies below $10^{18}$ eV the propelled ejecta, consisting of the fall-back neutron star crust material from the explosion, is the dominant…