arXiv subjects

P. Haensel

Publications and source records attributed to P. Haensel.

111 records · Page 7Linked to original sources

arXiv1996

Ferromagnetism of dense matter and magnetic properties of neutron stars

Possible consequences of ferromagnetic transition in dense matter suggested recently by Kutschera and W{ó}jcik, for the magnetic properties of neutron stars, are studied. Specific model of dense matter, in which a small admixture of protons is completely polarized due to their interaction with neutrons, is considered. Magnetic field of neutron stars with a ferromagnetic core is calculated within the framework of general relativity. Two types of boundary conditions at the ferromagnetic core edge are considered, corresponding to normal and superconducting liquid envelope, respectively. Numerical results for the neutron star magnetic dipole moment are confronted with pulsar timing. To be consistent with observations, ferromagnetic cores surrounded by a non-superconducting envelope, should consist of weakly ordered ferromagnetic domains. If domains are highly ordered, ferromagnetic core should be screened by a superconducting envelope.

astro-ph↗

arXiv1996

Electron $ν\barν$ Bremsstrahlung in a Liquid Phase of Neutron Star Crusts

Neutrino emissivity from the electron $ν\barν$ bremsstrahlung in the liquid layers of the neutron star crusts is studied. Nuclear composition of matter in neutron star crusts is considered for various scenarios of neutron star evolution. For the deep layers of the crust, the compositions of cold catalyzed matter, accreted matter and hot matter ($T \ga 5 \times 10^9$~K) are shown to be very different, and this implies differences in the neutrino emissivity at given density and temperature. Neutrino-pair bremsstrahlung, due to collisions of relativistic degenerate electrons in a Coulomb liquid of atomic nuclei, is considered. The neutrino energy loss rate is expressed in a simple form through a Coulomb logarithm $L$ -- a slowly varying function of density, temperature, and nuclear composition. Non-Born corrections, thermal width of electron Fermi sphere, and finite sizes of nuclei are taken into account. Implications for cooling of neutron stars are discussed.

astro-ph↗

arXiv1995

Fast Rotation of Neutron Stars

We show that for realistic equations of state of dense matter, the universal proportionality factor relating the maximum rotation rate of neutron stars due to mass-shedding limit to the mass and radius of maximum allowable mass configuration of non-rotating models results from a universal proportionality between masses and radii of static maximum-mass neutron stars and those of maximally rotating configurations. These empirical relations cannot be obtained in the slow rotation approximation.

astro-ph↗