Hypernuclear stars from relativistic Hartree-Fock density functional theory

Li, Jia Jie; Long, Wen Hui; Sedrakian, Armen

doi:10.1140/epja/i2018-12566-6

Cited by 52 publications

(56 citation statements)

References 145 publications

(202 reference statements)

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“…The onset of hyperons softens the high-density domain of the EoS and affects only the highmass domain of the MR diagram. Note that hyperons appear in compact stars with masses M/M ≥ 1.5 [38][39][40], but their effect on the mass of the star becomes sizable only for the most massive stars. The triplet configurations appear in this case for stars with masses above 1.5M .…”

Section: B Two Sequential Phase Transitionsmentioning

confidence: 99%

Relativistic hybrid stars with sequential first-order phase transitions and heavy-baryon envelopes

Sedrakian

Alford

2020

Phys. Rev. D

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We compute the mass, radius and tidal deformability of stars containing phase transitions from hadronic to quark phase(s). These quantities are computed for three types of hadronic envelopes: purely nuclear, hyperonic, and ∆-resonance-hyperon admixed matter. We consider either a single first-order phase transition to a quark phase with a maximally stiff equation of state (EoS) or two sequential first-order phase transitions mimicking a transition from hadronic (H) to a quark matter phase followed by a second phase transition to another quark phase. Such a construct emulates the results of the computations of the EoS which include 2SC and CFL color superconducting phases at low and high density. We explore the parameter space which produces low mass twin and triplet configurations where equal mass stars have substantially different radii and tidal deformabilities. We demonstrate that while for purely hadronic stiff EoS the obtained maximum mass is inconsistent with the upper limit on this quantity placed by GW170817, the inclusion of the hyperonic and ∆-resonance degrees of freedom, as well as the deconfinement phase transition at sufficiently low density, produce configuration of stars consistent with this limit. The obtained hybrid star configurations are in the mass range relevant for the interpretation of the GW170817 event. We compare our results for the tidal deformability with the limits inferred from GW170817 showing that the onset of non-nucleonic phases, such as ∆-resonance-hyperon admixed phase or/and the quark phase(s) is favored by this data if the nuclear EoS is stiff. Also, we show that low-mass twins and especially triplets proliferate the number of combinations of possible types of star that can undergo a merger event, the maximal number being six in the case of triplets. The prospects for uncovering the first-order phase transition(s) to and in quark matter via measurements of tidal deformabilities in merger events are discussed.

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Section: B Two Sequential Phase Transitionsmentioning

confidence: 99%

Relativistic hybrid stars with sequential first-order phase transitions and heavy-baryon envelopes

Sedrakian

Alford

2020

Phys. Rev. D

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“…For the evaluation of hyperon-σ-meson coupling constants, we consider the optical potentials of the Λ, Σ and Ξ hyperons in nuclear matter to be, U Λ (n 0 /5) = −0.67 MeV and further constraining the σ * -Ξ and σ * -Σ couplings via the relation [53] g…”

Section: Meson-baryon Coupling Parametersmentioning

confidence: 99%

Equation of State of Strongly Magnetized Matter with Hyperons and Δ-Resonances

Thapa

Sinha

et al. 2020

Particles

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We construct a new equation of state for the baryonic matter under an intense magnetic field within the framework of covariant density functional theory. The composition of matter includes hyperons as well as Δ-resonances. The extension of the nucleonic functional to the hypernuclear sector is constrained by the experimental data on Λ and Ξ-hypernuclei. We find that the equation of state stiffens with the inclusion of the magnetic field, which increases the maximum mass of neutron star compared to the non-magnetic case. In addition, the strangeness fraction in the matter is enhanced. Several observables, like the Dirac effective mass, particle abundances, etc. show typical oscillatory behavior as a function of the magnetic field and/or density which is traced back to the occupation pattern of Landau levels.

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“…For the S-wave Λ condensate, we use the rate derived in Paper I. For the P -wave hyperonic condensate we adopt the emission rate derived for neutrons (Leinson 2017) with appropriate changes in the condensate parameter and weak charges. Our strategy in studying the cooling of hypernuclear compact stars is to vary the masses of the stars in the range between 1 to 2M⊙.…”

Section: Thermal Evolution Of Hypernuclear Starsmentioning

confidence: 99%

Cooling of hypernuclear compact stars: Hartree–Fock models and high-density pairing

Raduta¹,

Sedrakian

et al. 2019

Monthly Notices of the Royal Astronomical Society

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The thermal evolution of hypernuclear compact stars is studied for stellar models constructed on the basis of covariant density functional theory in Hartree and Hartree-Fock approximation. Parametrizations of both types are consistent with the astrophysical mass constraints on compact stars and available hypernuclear data. We discuss the differences of these density functionals and highlight the effects they have on the composition and on the cooling of hypernuclear stars. It is shown that hypernuclear stars computed with density functional models that have a low symmetry energy slope, L, are fairly consistent with the cooling data of observed compact stars. The class of stellar models based on larger L values gives rise to the direct Urca process at low densities, which leads to significantly faster cooling. We conjecture high-density pairing for protons and Λ's in the P -wave channel and provide simple scaling arguments to obtain these gaps. As a consequence the most massive stellar models with masses 1.8 ≤ M/M ⊙ ≤ 2 experience slower cooling by hyperonic dUrca processes which involve Λ's and protons.

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Hypernuclear stars from relativistic Hartree-Fock density functional theory

Cited by 52 publications

References 145 publications

Relativistic hybrid stars with sequential first-order phase transitions and heavy-baryon envelopes

Relativistic hybrid stars with sequential first-order phase transitions and heavy-baryon envelopes

Equation of State of Strongly Magnetized Matter with Hyperons and Δ-Resonances

Cooling of hypernuclear compact stars: Hartree–Fock models and high-density pairing

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