Astrophysics with Radioactive Isotopes

Universal relations for rapidly rotating cold and hot hybrid stars

Not scheduled

20m

Oral Presentation

Speaker

Noshad Largani (University of Wroclaw )

Description

Various global parameters of compact stars can be related via some empirical relations, that are
independent of the equation of state (EOS). These are known as universal relations. They seem to
hold for the maximum mass and the corresponding radii of non-rotating and maximally rapidly
rotating configurations, as well as their moment of inertia. Numerous studies have focused on the
case of hadronic, zero-temperature EOS, as well as some including a first-order phase transition
from hadrons to deconfined quark matter in their interior. On the other hand, many astrophysical
scenarios, e.g., protoneutron stars that result from core-collapse supernovae and binary neutron star
mergers, feature finite temperatures. Therefore, the study of Ref. [1] focused on the universal
relations for isentropic hadronic EOS. In this presentation I will discuss the universal relation
results obtained in Ref. [2], which is an extension of the previous work including large,
representative samples of hadronic and hybrid EOS, i.e., featuring first-order hadron-quark phase
transitions, both for zero temperature as well as finite entropy per particle configurations.

References
[1] Khadkikar et al, ‘Maximum mass of compact stars from gravitational wave events with finite-
temperature equations of state’, Phys. Rev. C 103, 055811
[2] Khosravi et al, ‘Universal relations for rapidly rotating cold and hot hybrid stars’, Mon. Not. R.
Astron. Soc, (submitted) arxiv astro-ph.HE/2112.10439