The crust of rotating strange quark stars

Abstract

Calculations of the properties of rotating strange stars with crusts are performed within the framework of general relativity. We employ an equation of state (EOS) of strange quark matter based on the MIT Bag Model with massive strange quarks and lowest order QCD interactions. The crust is described by the BPS equation of state. A significant increase of the stellar radius is found close to the Keplerian (mass-shedding limit) configuration. This leads to the disappearance of the gap between the stellar surface and the innermost stable circular orbit (ISCO) at very high rotation rates, for a rather broad range of stellar masses. The Keplerian configuration for the strange star with crust corresponds to values of J, T/W which are about 20% smaller than in the case of bare strange stars. Because the Keplerian configuration is achieved due to the increase of the stellar oblateness, the Keplerian frequency (of the rotation) remains almost unaltered. The lack of the gap close to the Keplerian rotation could imply a more stringent limit on the frequency of the ISCO, if the existence of such a gap is supported by observations, as in the source 4U 1820-30 with the upper QPO frequency 1.07 kHz. During the spin-down of a magnetized strange quark star with crust, the crust matter is absorbed in the equatorial region by the strange matter core. The deconfinement of absorbed crust matter is a strongly exothermic process, which would influence the cooling curve of this compact object.

9 pages, 10 figures, accepted for publication in A&A

Cited by in corpus (25)

• Strange Quark Matter and Compact Stars
• Rotating Stars in Relativity
• Spectral Methods for Numerical Relativity
• Rotating Stars in Relativity
• Are small radii of compact stars ruled out by GW170817/AT2017gfo?
• Innermost stable circular orbit of spinning particle in charged spinning black hole background
• Are rotating strange quark stars good sources of gravitational waves?
• Fundamental physics and the absence of sub-millisecond pulsars
• Could the compact remnant of SN 1987A be a quark star?
• Implications of the Conformal Constraint on Sound Speed on the Radius of PSR J0952-0607 within Rastall Gravity
• On the minimum radius of strange stars with crust
• Strange stars with different quark mass scalings
• Lower limits on the maximum orbital frequency around rotating strange stars
• Spinning Particle Dynamics and ISCO in Covariant Loop Quantum Gravity
• Recycling strange stars to millisecond periods
• Quadratic Rastall Gravity: from low-mass HESS J1731-347 to high-mass PSR J0952-0607 pulsars
• Cooling of strange stars in the color-flavor locked phase with a rotating crust Cooling of strange stars in the color-flavor locked phase with a rotating crust
• Partially accreted crusts of neutron stars
• Consistency between deep crustal heating of strange stars in superbursters and soft X-ray transients
• Could strange stars be in the color-flavor-locked phase: Tested by their thermal evolutions
• Surface Electric Field of Bare Strange Stars
• Thermal evolution of rotating strange stars in color superconductivity phase
• Quasi-normal f-modes of anisotropic quark stars in full general relativity
• Thermal Evolution of Strange Stars
• Slowly rotating neutron stars and hadronic stars in chiral SU(3) quark mean field model