Observational constraints on hyperons in neutron stars

By B. Lackey, Mohit Nayyar, B. Owen. 2005

138 citations recorded by the source corpus.

The possibility that neutron stars may contain substantial hyperon populations has important implications for neutron-star cooling and, through bulk viscosity, the viability of the r-modes of accreting neutron stars as sources of persistent gravitational waves. In conjunction with laboratory measurements of hypernuclei, astronomical observations were used by Glendenning and Moszkowski [Phys. Rev. Lett. 67, 2414 (1991)] to constrain the properties of hyperonic equations of state within the framework of relativistic mean-field theory. We revisit the problem, incorporating recent measurements of high neutron-star masses and a gravitational redshift. We find that only the stiffest of the relativistic hyperonic equations of state commonly used in the literature is compatible with the redshift. However, it is possible to construct stiffer equations of state within the same framework which produce the observed redshift while satisfying the experimental constraints on hypernuclei, and we do this. The stiffness parameter that most affects the redshift is not the incompressibility but rather the hyperon coupling. Nonrelativistic potential-based equations of state with hyperons are not constrained by the redshift, primarily due to a smaller stellar radius.

Subfields: Astronomy and Astrophysics, Geophysics

View Paper: https://www.semanticscholar.org/paper/d3ee230534aad8a448f7e4b90befbd12d2dea700

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Citations in the corpus

Relativistic Shapiro delay measurements of an extremely massive millisecond pulsar (2019, background): “.05M that is in possible tension with our 2:17+0:11 0:10 M measurement lower bound. A similar situation arises with \H4," one of the stier hyperon-based EoS from Lackey, Nayyar, and Owen (2006) [15]. This model allows only for a 2.03-M neutron star, which is signicantly less than the lower boun”
Tidal Deformability from GW170817 as a Direct Probe of the Neutron Star Radius (2018, background): “As shown in Figure 1, 3 this rules out the EOS that predict the largest radii, such as the hyperonic EOS H4 (Lackey et al. 2006) and the field theoretic nucleonic EOS with a low symmetry energy of 25 MeV, MS1b (Müller & Serot 1996).”
Physics, Astrophysics and Cosmology with Gravitational Waves (2009, background): “However, the instability is, like other CFS instabilities, sensitive to viscosity, and there is great uncertainty about the amount of viscosity inside neutron stars [240, 228, 35].”
Approximate Universal Relations for Neutron Stars and Quark Stars (2016, unknown): “1 [118], G4 [121], GCR [135], MPa [136].”
A two-solar-mass neutron star measured using Shapiro delay (2010, unknown): “97(4)M[ Dispersion-derived distance{ 1.”