We present a detailed investigation of atmospheres around accreting neutron stars with high magnetic field (B ∼> 1012 G) and low luminosity (L ∼< 1033 erg/s). We compute the atmospheric structure, intensity and emergent spectrum for a plane–parallel, pure hydrogen medium by solving the transfer equations for the normal modes coupled to the hydrostatic and energy balance equations. The hard tail...

The multifaceted role of the density dependent nuclear symmetry energy in the nuclear astrophysics involving neutron stars is highlighted. Efforts toward a model independent determination of the dense matter equation state through a deconstruction of the neutron star structure equation utilizing the masses and radii of several individual neutron stars are described. The need for observational d...

Considering the non-Newtonian gravity proposed in grand unification theories, we show that the stability and observed global properties of neutron stars cannot rule out the supersoft nuclear symmetry energies at suprasaturation densities. The degree of possible violation of the inverse-square law of gravity in neutron stars is estimated using an equation of state of neutron-rich nuclear matter ...

We compute and present the distribution in mass of single and binary neutron stars, strange stars, and black holes. The calculations were performed using a stellar population synthesis code. We follow all phases of single and binary evolution, starting from a ZAMS binary and ending in the creation of one compact object (neutron star, black hole, strange star) and a white dwarf, or two compact o...

We study the conditions for convective instability in rotating, non-magnetic proto–neutron stars. The criteria that determine stability of nascent neutron stars are analogous to the Solberg–Høiland conditions but including the presence of lepton gradients. Our results show that, for standard angular velocity profiles, convectively unstable modes with wave-vectors parallel to the rotation axis a...

Abstract The oscillation of neutron n into mirror $$n'$$ n ′ , its mass degenerate partner from dark sector, can gradually transform the stars mixed consisting in part matter. In quark $$n-n'$$ - transitions are suppressed. We stu...

The Chandrasekhar limit for quark stars is evaluated from simple energy balance relations, as proposed by Landau for white dwarfs or neutron stars. It has been found that the limit for quark stars depends on, in addition to the fundamental constants, the Bag constant. Compact objects like the white dwarfs and neutron stars have been a topic of interest for several decades. These objects are pro...

Observations of Type I X-ray bursts have long been taken as evidence that the sources are neutron stars. Black body models approximate the spectral data and imply a suddenly heated neutron star cooling over characteristic times of seconds to minutes. The phenomena are convincingly explained in terms of nuclear burning of accreted gas on neutron stars with low mass companion stars. Prospects are...

We use a collection of 14 well-measured neutron-star masses to strengthen the case that a substantial fraction of these neutron stars were formed via electron-capture (e-capture) supernovae (SNe) as opposed to Fe corecollapse SNe. The e-capture SNe are characterized by lower resultant gravitational masses and smaller natal kicks, leading to lower orbital eccentricities when the e-capture SN has...

We argue that the strong interaction between protons and neutrons in the asymmetric liquid (neutron star) distorts strongly proton Fermi surface. We use the Feynman diagram approach to calculate probability of triple (e-p-n) short range correlations in terms of the short range (p-n) correlations and ultrarelativistic Coulomb (p-e) interaction. We find that these correlations lead to holes in (e...