Discriminating hadronic and quark stars through gravitational waves of fluid pulsation modes

Abstract

We investigate non-radial oscillations of hadronic, hybrid and pure\nself-bound strange quark stars with maximum masses above the mass of the\nrecently observed massive pulsars PSR J1614-2230 and PSR J0348-0432 with $M\n\\approx 2 M_{\\odot}$. For the hadronic equation of state we employ different\nparametrizations of a relativistic mean-field model and for quark matter we use\nthe MIT bag model including the effect of strong interactions and color\nsuperconductivity. We find that the first pressure mode for strange quark stars\nhas a very different shape than for hadronic and hybrid stars. For strange\nquarks stars the frequency of the p1 mode is larger than 6 kHz and diverge at\nsmall stellar masses, but for hadronic and hybrid stars it is in the range 4-6\nkHz. This allows an observational identification of strange stars even if extra\ninformation such as the mass, the radius or the gravitational redshift of the\nobject is unavailable or uncertain. Also, we find as in previous works that the\nfrequency of the g-mode associated with the quark-hadron discontinuity in a\nhybrid star is in the range 0.4-1 kHz for all masses. Thus, compact objects\nemitting gravitational waves above 6 kHz should be interpreted as strange quark\nstars and those emitting a signal within 0.4-1 kHz should be interpreted as\nhybrid stars.\n