The cooling of compact isolated objects for different values of the gravitational mass has been simulated for two alternative assumptions. One is that the interior of the star is purely hadronic[1] and second that the star can have a rather large quark core [2]. It has been shown that within a nonlocal chiral quark model the critical density for a phase transition to color superconducting quark...

The inner layers of a neutron star crust, composed of a Coulomb lattice of neutron rich nuclear clusters immersed in a sea of “free” superfluid neutrons, are closely analogous to periodic condensed matter systems such as electronic, photonic or phononic crystals. Applying methods from solid state physics to the neutron star context, we study the transport properties of those “free” neutrons for...

A review of properties of matter in the interior of neutron stars is given. Particular attention is paid to recent many-body theory calculations of the properties of dense matter. Among topics discussed are the strong increase of tensor correlations at relatively low densities, the “relativistic boost term” in the interaction, and the sensitivity of properties of neutron star models to three-bo...

I review attempts made to determine the properties of neutron stars. The focus is on the maximum mass that a neutron star can have, or, conversely, the minimum mass required for the formation of a black hole. There appears to be only one neutron star for which there is strong evidence that its mass is above the canonical 1.4M⊙, viz., Vela X-1, for which a mass close to 1.9M⊙ is found. Prospects...

The properties of tectonic earthquake sources are compared with those deduced here for fault planes in solid neutron-star matter. The conclusion that neutron-star matter cannot exhibit brittle fracture at any temperature or magnetic field strength is significant for current theories of pulsar glitches, and of the anomalous X-ray pulsars and soft-gamma repeaters. Subject headings: stars:neutron ...

We report spectral and variability analysis of two quiescent low mass X-ray binaries (X5 and X7, previously detected with the ROSAT HRI) in a Chandra ACIS-I observation of the globular cluster 47 Tuc. X5 demonstrates sharp eclipses with an 8.666±0.01 hr period, as well as dips showing an increased NH column. The thermal spectra of X5 and X7 are well-modeled by unmagnetized hydrogen atmospheres ...

The orbital parameters of the recently discovered transient burster/pulsar GRO J1744–28 indicate that this system is a low-mass X-ray binary in an advanced stage of its mass transfer, with several tenths of a solar mass already transferred from the donor to the compact star. All neutron stars known to have accreted such an amount have very weak magnetic fields, and this has led to the idea that...

We study systematically the ≃ 0.1 − 1200 Hz quasi-periodic oscillations (QPOs) and broad noise components observed in the power spectra of non-pulsing neutron-star and black-hole low-mass X-ray binaries. We show that among these components we can identify two, occurring over a wide range of source types and luminosities, whose frequencies follow a tight correlation. The variability components i...

Neutron stars formed in Type II supernovae are likely to be initially obscured by late-time fallback. Although much of the late-time fallback is quickly accreted via neutrino cooling, some material remains on the neutron star, forming an atmosphere which slowly accretes through photon emission. In this paper, we derive structure equations of the fallback atmosphere and present results of one-di...

The physics of neutron star crusts is vast, involving many different research fields, from nuclear and condensed matter physics to general relativity. This review summarizes the progress, which has been achieved over the last few years, in modeling neutron star crusts, both at the microscopic and macroscopic levels. The confrontation of these theoretical models with observations is also briefly...