Related papers: The missing compact star of SN1987A: a solid quark…
The magnetar model and a solid quark star model for anomalous X-ray pulsars/soft gamma-ray repeaters (AXPs/SGRs) are discussed. Different manifestations of pulsar-like stars are speculated to be due to both their nature (e.g., mass and…
We investigate the thermal evolution of quark stars with and without a hadronic crust using an equation of state derived from perturbative QCD that incorporates the running of the strong coupling and the strange quark mass. Our analysis…
It is conventionally thought that the state equation of dense matter softens and thus cannot result in high maximum mass if pulsars are quark stars, and that a recently discovered $2M_\odot$ pulsar (PSR J1614-2230) may make quark stars to…
A circumstellar corona is proposed for a strange quark-cluster star during an accretion phase, that could be essential to understand the observations of the puzzling symbiotic X-ray system, 4U 1700+24. The state of cold matter at…
I discuss the lack of observational evidence that magnetars are formed as rapidly rotating neutron stars. Supernova remnants containing magnetars do not show the excess of kinetic energy expected for such a formation scenario, nor is there…
Strange quark matter with the density of ~ 5\times 10^{14} g cm^{-3} might exist up to the surface of a strange star. This differs qualitatively from the case of a neutron star and opens observational possibilities to distinguish strange…
Recent models of carbon ignition on accreting neutron stars predict superburst ignition depths that are an order of magnitude larger than observed. We explore a possible solution to this problem, that the compact stars in low mass X-ray…
In the context of the standard model of particle physics, there is a definite upper limit to the density of stable compact stars. However, if there is a deeper layer of constituents, below that of quarks and leptons, stability may be…
Recently, observations of compact stars have provided new data of high accuracy which put strong constraints on the high-density behaviour of the equation of state of strongly interacting matter otherwise not accessible in terrestrial…
It depends on the state of matter at supra-nuclear density to model pulsar's structure, which is unfortunately not certain due to the difficulties in physics. In cold quark matter at realistic baryon densities of compact stars (with an…
We review the status of research on the cooling of compact stars, with emphasis on the influence of color superconducting quark matter phases. Although a consistent microscopic approach is not yet available, severe constraints on the phase…
The detection of an unexpected $\sim 2.5 M_{\odot}$ component in the gravitational wave event GW190814 has puzzled the community of High-Energy astrophysicists, since in the absence of further information it is not clear whether this is the…
A number of observed phenomena associated with individual neutron star systems or neutron star populations find explanations in models in which the neutron star crust plays an important role. We review recent work examining the sensitivity…
The neutrino signal from SN1987A confirmed the core-collapse scenario and the possible formation of a neutron star. Although this compact object has eluded all observations, theoretical and numerical developments have allowed a glimpse of…
This paper gives an overview of the properties of all possible equilibrium sequences of compact strange-matter stars with nuclear crusts, which range from strange stars to strange dwarfs. In contrast to their non-strange counterparts,…
Witten's conjecture about strange quark matter (`Strange Matter') being the ground state of QCD at finite baryon number is presented and stars made of strange matter (`Strange Stars') are compared to neutron stars. The only observable way…
Recent indications for high neutron star masses (M \sim 2 M_sun) and large radii (R > 12 km) could rule out soft equations of state and have provoked a debate whether the occurence of quark matter in compact stars can be excluded as well.…
After a brief non technical introduction of the basic properties of strange quark matter (SQM) in compact stars, we consider some of the late important advances in the field, and discuss some recent astrophysical observational data that…
According to the hypothesis that strange quark matter may be the true ground state of matter at extremely high densities, strange quark stars should be stable and could exist in the Universe. It is possible that pulsars may actually be…
We report new simulations of cooling of compact stars containing quark cores and updated fits to the Cas A fast cooling data. Our model is built on the assumption that the transient behaviour of the star in Cas A is due to a phase…