Strangeness in Compact Stars

Abstract

We discuss the impact of strange hadrons, in particular hyperons, on the gross features of compact stars and on core-collapse supernovae. Hyperons are likely to be the first exotic species which appears around twice normal nuclear matter density in the core of neutron stars. Their presence largely influences the mass-radius relation of compact stars, the maximum mass, the cooling of neutron stars, the stability with regard to the emission of gravitational waves from rotationpowered neutron stars and the possible early onset of the QCD phase transition in core-collapse supernovae. We outline also the constraints from subthreshold kaon production in heavy-ion collisions for the maximum possible mass of neutron stars.

Quark-meson coupling model, nuclear matter constraints, and neutron star properties

“…This is in contrast to a number of other relativistic models which do predict the threshold to occur, even prior to that of the [65,66]. We note that Schaffner-Bielich [65] considered a phenomenological modification of the potential with additional repulsion, which significantly raised its threshold density.…”

Hyperon-Nucleon Interactions and the Composition of Dense Nuclear Matter

“…2 indicate that the repulsion in the nΣ − system is inadequate to exclude the presence of Σ − 's in neutron star matter, a conclusion that is consistent with previous phenomenological modeling (for a review, see Ref. [47]). To conclude, we have performed the first LQCD predictions for hypernuclear physics, the 1 S 0 and 3 S 1 nΣ − scattering phase shifts shown in Fig.…”

Equation of State of Dense Matter and Consequences for Neutron Stars

“…This is in contrast to a number of other relativistic models which do predict the Σ threshold to occur, even prior to that of the Λ [22,23]. We note that Schaffner-Bielich [22] considered a phenomenological modification of the Σ potential with additional repulsion, which significantly raised its threshold density.…”