Thermal evolution of rotating hybrid stars

Abstract

As a neutron star spins down, the nuclear matter continuously is converted into quark matter due to the core density increase and then latent heat is released. We have investigated the thermal evolution of neutron stars undergoing such deconfinement phase transition. We have taken into account the conversion in the frame of the general theory of relativity. The released energy has been estimated as a function of change rate of deconfinement baryon number. Numerical solutions to cooling equation are obtained to be very different from the without heating effect. The results show that neutron stars may be heated to higher temperature which is well-matched with pulsar's data despite onset of fast cooling in neutron stars with quark matter core. It is also found that heating effect has magnetic field strength dependence. This feature could be particularly interesting for high temperature of low-field millisecond pulsar at late stage. The high temperature could fit the observed temperature for PSR J0437-4715.Comment: 7 pages, 7 figure

Novel non-equilibrium phase transition caused by non-linear hadronic-quark phase structure

“…One particular example is the delayed cooling of isolated neutron stars and the old neutron stars with high thermal luminosity. The neutron stars with quark matter core are not so cold by heating [13]. The old pulsar, PSR J0437-4715, is inferred as high thermal luminosity, the follow-up of which has been done by Kargaltsev et al [14,15].…”

Microscopic Magnetic Dipole Radiation in Neutron Stars

“…2 shows that, there is a plateau in the late stage of NS cooling curves. This plateau can be compared with that of Kang's (2007).…”

The effect of deconfinement phase transition on rotochemical deviations in stars containing mixed-phase matter

“…Therefore, we have where x indicates the d, s, n fraction of baryon density and E xx is the partial derivative of chemical energy per baryon (Cheng & Dai 1996). In the hadron–quark mixed phase, hadrons and quarks undergo direct Urca processes (Kang & Zheng 2007). Γ d , Γ s and Γ n are the reaction rates per baryon (Haensel 1992; Dai, Lu & Peng 1993).…”

“…Some mechanisms have been extensively discussed. These include the mutual friction between superfluid and normal components of the star (Shibazaki & Lamb 1989), the heat released through deconfinement phase transition (Kang & Zheng 2007) and the release of strain energy stored by the solid crust due to spin‐down deformation (Cheng et al 1992).…”