Constraints of the maximum mass of quark stars based on post-merger evolutions

Zhou, Yurui

We semi-analytically investigate the post-merger evolution of the binary quark star merger. The effective-one-body method is employed to estimate the energy and angular momentum dissipation due to gravitational waves in the inspiral phase. Three major mechanisms of energy and angular momentum dissipation are considered in the post-merger phase: mass outflow， neutrinos and gravitational waves. The fraction of each mechanism could be determined by baryon number， energy and angular momentum conservation laws as well as the equilibrium model for rotating quark stars. Applying this analysis to the GW170817 event suggests two important conclusions: 1) a remnant quark star whose mass is smaller than the maximum mass of a uniformly rotating quark star can collapse in a short timescale as the angular momentum contained in the remnant quark star might not be large enough to reach the mass shedding limit; 2) considering a general quark star equation of state model， a constraint on the maximum mass of cold and non-rotating quark stars is found as $M_{\mathrm{TOV}}\lesssim2.34\，M_{\odot}$， assuming a delayed collapse occurred for the GW170817 event. These constraints could be improved with future merger events， once there are more evidences on its post-merger evolution channel or information on the amount of post-merger gravitational wave and neutrino emissions inferred from the multi-messenger observations.