相关论文: What can the redshift observed in EXO 0748-676 tel…
The X-ray emission of RXJ1856.5-3754 has been found to coincide to unprecedented accuracy with that of a blackbody, of radius 5.8+-0.9 km for the measured parallax distance of 140 pc (Burwitz et al. 2001, Drake et al. 2002). If the emission…
The interiors of neutron stars contain matter at very high densities, in a state that differs greatly from those found in the early universe or achieved at terrestrial experiments. Matter in these conditions can only be probed through…
The determination of mass and radius of a single neutron star EXO 0748-676 has been reported recently. Also, the estimate of radius from the measurement of moment of inertia of pulsar A in double pulsar system PSR J0737-3039 would be…
Determining the maximum possible neutron star (NS) mass places limits on the equation of state (EoS) of ultra-dense matter. The mass of NSs in low mass X-ray binaries can be determined from the binary mass function, providing independent…
The observed evidence for the existence of strange stars and the concomitant observed masses and radii are used to derive an interpolation formula for the mass as a function of the radial coordinate. The resulting general mass function…
We compute the maximum mass of moderately rotating strange stars as a function of the strange quark mass, of the QCD coupling constant, $\alpha_c$, and of the bag constant (vacuum energy density), $B$, in the MIT bag model of quark matter…
X-ray observations of EXO 0748-676 during thermonuclear bursts revealed a set of narrow absorption lines that potentially originate from the stellar photosphere. The identification of these lines with particular atomic transitions led to…
We have observed an unusually strong X-ray burst as a part of our regular eclipse timing observations of the low mass binary system EXO0748-676. The burst peak flux was 5.2x10^-8 ergs cm^-2 s^-1, approximately five times the normal peak…
We analyse four XMM-Newton observations of the neutron-star low-mass X-ray binary EXO 0748$-$676 in quiescence. We fit the spectra with an absorbed neutron-star atmosphere model, without the need for a high-energy (power-law) component;…
Strange quark stars with a crust and strange dwarfs consisting of a compact strange quark core and an extended crust are investigated in terms of a bag model. The crust, which consists of atomic nuclei and degenerate electrons, has a…
Recently there is a suggestion about the star RXJ1856.5$-$3754, being a possible candidate for quark star. While from the estimates of the radiation radius, given by the authors, it does not seem to fit with any of the known models for such…
During the last couple of years astronomers and astrophysicists have been debating on the fact whether the so called `strange stars' - stars made up of strange quark matter, have been discovered with the candidates like SAX J1808.4-3658, 4U…
The Chandrasekhar limit for strange stars described by a linear equation of state (describing quark matter with density-dependent quark masses) is evaluated. The maximum mass and radius of the star depend on the fundamental constants and on…
There are three categories of stars whose masses have been found accurately in recent times: (1) two for which Shapiro delay is used which is possible due to GR light bending as the partner is heavy : PSR J1614-2230 and PSR J1903+0327 (2)…
We present phase resolved optical spectroscopy and X-ray timing of the neutron star X-ray binary EXO 0748-676 after the source returned to quiescence in the fall of 2008. The X-ray light curve displays eclipses consistent in orbital period,…
We investigate the equations of state for pure neutron matter and strange hadronic matter in $\beta$-equilibrium, including $\Lambda$, $\Sigma$ and $\Xi$ hyperons. The masses and radii of pure neutron stars and strange hadronic stars are…
The discovery of photospheric absorption lines in XMM-Newton spectra of the X-ray bursting neutron star in EXO0748-676 by Cottam and collaborators allows us to constrain the neutron star mass-radius ratio from the measured gravitational…
We reexamine the surface composition of strange stars. Strange quark stars are hypothetical compact stars which could exist if strange quark matter was absolutely stable. It is widely accepted that they are characterized by an enormous…
We calculate the equation of state of strange quark matter and the interior structure of strange quark stars in a Dyson-Schwinger quark model within rainbow or Ball-Chiu vertex approximation. We emphasize constraints on the parameter space…
The minimum value of the radius of strange star covered by the crust of nuclear matter is determined. The results for the maximum possible thickness of the crust (up to the neutron drip) as well as the possibility of thinner crust…