Recent observations and theoretical investigations of neutron stars indicate that their atmospheres consist not of hydrogen or iron but possibly heavier elements such as helium. We calculate the ionization and dissociation equilibrium of helium in the conditions found in the atmospheres of magnetized neutron stars. For the first time this investigation includes the internal degrees of freedom o...

Properties of non-rotating and rapidly rotating protoneutron stars and neutron stars are investigated. Protoneutron stars are hot, lepton rich neutron stars which are formed in TypeII supernovae. The hot dense matter is described by a realistic equation of state which is obtained by extending a recent approach of Myers and Świa̧tecki to the nuclear mass formula. We investigate the properties of ...

The dynamics, time evolution of the mass distribution, and gravitational wave signature of coalescing neutron stars described by polytropes are compared with three simulations published previously: (a) “Run 2” of Zhuge et al. (1994), (b) “Model III” of Shibata et al. (1992), and (c) “Model A64” of Ruffert et al. (1996). We aim at studying the differences due to the use of different numerical me...

We derive the bulk viscous damping timescale of hybrid stars, neutron stars with quark matter core. The r-mode instability windows of the stars show that the theoretical results are consistent with the rapid rotation pulsar data, which may give an indication for the existence of quark matter in the interior of neutron stars. Hybrid stars instead of neutron or strange stars may lead to submillis...

Creation of strange quark stars through strong interaction deconfinement is studied based on modern estimates of hyperon formation in neutron stars. The hyperon abundance is shown to be large enough so that if strange quark matter (SQM) is the true ground state of matter, the deconfinement density should be at most 2.5−3 times the nuclear saturation density. If so, deconfinement occurs in neutr...

As it is well known for stiff equations of state an existence of neutron stars with masses ∼ 2M⊙ is possible. Especially interesting possibility is opened if the equation of state based on the Skyrme theory is realized in nature. This equation of state was proposed recently by Ouyed and Butler. We discuss different channels of formation of massive rapidly rotating neutron stars. We use a popula...

high spin states in the neutron rich nucleus 191os has been populated for the first time using the82se+192os deep-inelastic reaction at 460 mev beam energy using the alpi accelerators at the laboratorynazionali di legnaro, italy. high fold γ-γ coincidences were acquired with the 4π spectrometer gaspdetector array, consisting of 40 compton-suppressed, large-volume germanium detectors with an inn...