Radial Modes of Hot Neutrino-Trapped Hybrid Stars
Abstract
We study the fundamental radial oscillation mode of hot hadronic and hybrid stars under conditions relevant to proto-neutron stars and neutron-star merger remnants. The stellar backgrounds are constructed from finite-temperature equations of state with a covariant density functional for hadronic matter and three-flavor 2SC quark matter at high density. We consider two isentropic configurations in both neutrino-transparent matter and with trapped electron neutrinos at fixed electron-lepton fraction. For trapped matter we compare a Gibbs-type construction with global electron-lepton-number conservation to a locally constrained Maxwell-type prescription; in both cases the fixed-entropy stellar equation of state contains an extended coexistence region and no sharp interface requiring conversion rate-dependent junction conditions. We find that the fundamental radial frequency follows the corresponding purely hadronic sequence up to the onset of deconfinement and then decreases relative to it. Neutrino trapping shifts this dynamical signature to larger stellar masses and central pressures, reflecting the delayed appearance of quark matter. The Maxwell-type prescription moves the onset of deconfinement to still higher central pressure and produces a more rapid decrease of the mode frequency near the stability limit. We quantify the deconfinement effect through the fractional frequency shift between hybrid and hadronic stars at equal gravitational mass. These results show that the fundamental radial mode provides a sensitive dynamical probe of the interplay among entropy, lepton trapping, phase-transition construction, and quark deconfinement in hot compact stars.
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BibTeX
@misc{rau2026radial,
title = {{Radial Modes of Hot Neutrino-Trapped Hybrid Stars}},
author = {Peter B. Rau and Andrea Sabatucci and Armen Sedrakian},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.07241},
eprint = {2610.07241},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.07241},
}
RIS
TY - UNPB
TI - Radial Modes of Hot Neutrino-Trapped Hybrid Stars
AU - Peter B. Rau
AU - Andrea Sabatucci
AU - Armen Sedrakian
PY - 2026
DA - 2026/10/05
PB - arXiv
DO - 10.48550/arxiv.2610.07241
UR - https://arxiv.org/abs/2610.07241
AB - We study the fundamental radial oscillation mode of hot hadronic and hybrid stars under conditions relevant to proto-neutron stars and neutron-star merger remnants. The stellar backgrounds are constructed from finite-temperature equations of state with a covariant density functional for hadronic matter and three-flavor 2SC quark matter at high density. We consider two isentropic configurations in both neutrino-transparent matter and with trapped electron neutrinos at fixed electron-lepton fraction. For trapped matter we compare a Gibbs-type construction with global electron-lepton-number conservation to a locally constrained Maxwell-type prescription; in both cases the fixed-entropy stellar equation of state contains an extended coexistence region and no sharp interface requiring conversion rate-dependent junction conditions. We find that the fundamental radial frequency follows the corresponding purely hadronic sequence up to the onset of deconfinement and then decreases relative to it. Neutrino trapping shifts this dynamical signature to larger stellar masses and central pressures, reflecting the delayed appearance of quark matter. The Maxwell-type prescription moves the onset of deconfinement to still higher central pressure and produces a more rapid decrease of the mode frequency near the stability limit. We quantify the deconfinement effect through the fractional frequency shift between hybrid and hadronic stars at equal gravitational mass. These results show that the fundamental radial mode provides a sensitive dynamical probe of the interplay among entropy, lepton trapping, phase-transition construction, and quark deconfinement in hot compact stars.
ER -