2023MNRAS.522.3263I -
Mon. Not. R. Astron. Soc., 522, 3263-3270 (2023/July-1)
Exotic baryons in hot neutron stars.
ISSIFU A., MARQUEZ K.D., PELICER M.R. and MENEZES D.P.
Abstract (from CDS):
We study the nuclear isentropic equation of state for a stellar matter composed of nucleons, hyperons, and Δ-resonances. We investigate different snapshots of the evolution of a neutron star, from its birth as a lepton-rich proto-neutron star in the aftermath of a supernova explosion to a lepton-poor regime when the star starts cooling to a catalysed configuration. We use a relativistic model within the mean-field approximation to describe the hot stellar matter and adopt density-dependent couplings adjusted by the DDME2 parameterization. We use baryon-meson couplings for the spin-1/2 baryonic octet and spin-3/2 decuplet determined in a unified manner relying on SU(6) and SU(3) symmetry arguments. We observe that Λ is the dominant exotic particle in the star at different entropies for both neutrino-free and neutrino-trapped stellar matter. For a fixed entropy, the inclusion of new particles (hyperons and/or delta resonances) in the stellar matter decreases the temperature. Also, an increase in entropy per baryon (1-2) with decreasing lepton number density (0.4-0.2) leads to an increase in stellar radii and a decrease in its mass due to neutrino diffusion. In the neutrino transparent matter, the radii decrease from entropy per baryon 2 to $T\, =\, 0$ without a significant change in stellar mass.
Abstract Copyright:
© 2023 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society
Journal keyword(s):
stars: neutron - stars: protostars - ISM: supernova remnants
Simbad objects:
1
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