Tidal Deformations of Hybrid Stars with Sharp Phase Transitions and Elastic Crusts

Author(s)

Pereira, Jonas P. ^[1] ; Bejger, Michal ^[1] ; Andersson, Nils ^[2] ; Gittins, Fabian ^[2]

Affiliation

^[1] Polish Acad Sci, Nicolaus Copernicus Astron Ctr, Bartycka 18, PL-00716 Warsaw - Poland

^[2] Univ Southampton, Math Sci & STAG Res Ctr, Southampton SO17 1BJ, Hants - England

• Document type: Journal article
• Source: ASTROPHYSICAL JOURNAL; v. 895, n. 1 MAY 2020.
• Web of Science Citations: 0

Abstract

Gravitational wave astronomy is expected to provide independent constraints on neutron-star properties, such as their equation of state. This is possible with the measurements of binary components' tidal deformability, which alter the point-particle gravitational waveforms of neutron-star binaries. Here, we provide a first study of the tidal deformability effects due to the elasticity/solidity of the crust (hadronic phase) in a hybrid neutron star, as well as the influence of a quark-hadronic phase density jump on tidal deformations. We employ the framework of non-radial perturbations with zero frequency and study hadronic phases presenting elastic aspects when perturbed (with the shear modulus approximately 1% of the pressure). We find that the relative tidal deformation change in a hybrid star with a perfect-fluid quark phase and a hadronic phase presenting an elastic part is never larger than about 2%-4% (with respect to a perfect-fluid counterpart). These maximum changes occur when the elastic region of a hybrid star is larger than approximately 60% of the star's radius, which may happen when its quark phase is small and the density jump is large enough, or even when a hybrid star has an elastic mixed phase. For other cases, tidal deformation changes due to an elastic crust are negligible (10(-5)-10(-1)%) and, therefore, unlikely to be measured even with third generation detectors. Thus, only when the size of the elastic hadronic region of a hybrid star is over half of its radius, could the effects of elasticity have a noticeable impact on tidal deformations. (AU)

• FAPESP's process: 17/21384-2 - Asteroseismology of quasi-periodic oscillations and constraints to hybrid neutron star models
• Grantee: Jonas Pedro Pereira
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• FAPESP's process: 15/04174-9 - Some consequences of the microphysics of volumes and surfaces in compact systems
• Grantee: Jonas Pedro Pereira
• Support Opportunities: Scholarships in Brazil - Post-Doctoral