We discuss pycnonuclear burning of highly exotic atomic nuclei in deep crusts of neutron stars, at densities up to 10 g cm. As an application, we consider pycnonuclear burning of matter accreted on a neutron star in a soft X-ray transient (SXT, a compact binary containing a neutron star and a lowmass companion). The energy released in this burning, while the matter sinks into the stellar crust ...

Until a few years ago the common understanding was that neutron stars, the compact remnants of massive stars, have a canonical mass of about 1.4 MA. Recent observations with VLT/UVES support the view that the neutron stars in high-mass X-ray binaries display a relatively large spread in mass, ranging from the theoretical lower mass limit of 1 MA up to over 2 MA. Such a mass distribution provide...

Transitions of nuclear compositions in the crust of a neutron star induced by stellar spin-down are evaluated at zero temperature. We construct a compressible liquiddrop model for the energy of nuclei immersed in a neutron gas, including pairing and shell correction terms, in reference to the known properties of the ground state of matter above neutron drip density, 4.3 × 10 g cm. Recent experi...

Properties of dense nucleon matter and the structure of neutron stars are studied using variational chain summation methods and the new Argonne v18 two-nucleon interaction, which provides an excellent fit to all of the nucleonnucleon scattering data in the Nijmegen data base. The neutron star gravitational mass limit obtained with this interaction is 1.67M⊙ . Boost corrections to the two-nucleo...

Recent discovery of kilohertz quasi-periodic brightness oscillations of low mass X-ray binaries (LMXBs) has attracted attention to highly relativistic periodic motion near accreting neutron stars. Most models proposed so far involve (almost) inertial motion in the vicinity of the stars’ innermost stable circular orbits. In the present paper we study general-relativistic circular and eccentric o...

Like white dwarfs, neutron stars are strongly degenerate compact objects of roughly one solar mass. But whereas white dwarfs are supported against gravity by the zero-point motion of electrons (electron degeneracy pressure), neutron stars, as the name suggests, consist mostly of neutrons and are supported by the zero-point motion and interactions among the latter particles. The existence of neu...

Employing spectra obtained with the new Keck I HIRES near-UV sensitive detector, we have performed a comprehensive chemical composition analysis of the binary blue metal-poor star CS29497-030. Abundances for 29 elements and upper limits for an additional seven have been derived, concentrating on elements largely produced via neutron-capture nucleosynthesis. Included in our analysis are the two ...

Context. Only two planetary systems around old ms-pulsars are currently known. Young radio pulsars and radio-quiet neutron stars cannot be covered by the usually-applied radio pulse timing technique. However, finding substellar companions around these neutron stars would be of great interest – not only because of the companion’s possible exotic formation but also due to the potential access to ...

Observations of thermal radiation from neutron stars allow one to measure the surface temperatures and confront them with cooling scenarios. Detection of gravitationally redshifted spectral lines can yield the mass-to-radius ratio. In the few cases when the distance is known, one can measure the neutron star radius, which is particularly important to constrain the equation of state of the super...