2021MNRAS.506.5916L

We constrain the equation of state of quark stars within the Bayesian statistical approach using the mass and radius measurements of PSR J0030+0451 from NICER. Three types of bag models, with and without non-zero finite quark mass and/or superfluidity, are employed for quark stars made up with self-bound strange quark matter. We find the 90 per cent posterior credible boundary around the most probable values of the quark star maximum mass is M_TOV=2.38_–0.23^+0.26 M_☉, within the model flexibility of the finite quark mass, the quark pairing gap, and the perturbative contribution from the one-gluon exchange. The radius of a canonical 1.4 M_☉ quark star is R_1.4∼12.3 km, smaller than the results based on neutron star models.