2023ApJ...951..144E -
Astrophys. J., 951, 144 (2023/July-2)
Implications of the Conformal Constraint on Sound Speed on the Radius of PSR J0952-0607 within Rastall Gravity.
EL HANAFY W. and AWAD A.
Abstract (from CDS):
It has been shown that the nonminimal coupling between geometry and matter can provide models for massive compact stars that are consistent with the conformal bound on the sound speed, $0\leqslant {c}_{s}^{2}\leqslant {c}^{2}/3$, where the core density approaches a few times the nuclear saturation density. We impose the conformal upper bound on the sound speed on Rastall's field equations of gravity, with Krori-Barua potentials in the presence of an anisotropic fluid as a matter source, to estimate the radius of the most massive pulsar ever observed, PSR J0952-0607. For its measured mass M = 2.35 ± 0.17 M⊙, we obtain a radius R = 14.087 ± 1.0186 km as inferred by the model. We investigate a possible connection between Rastall gravity and the MIT bag model with an equation of state, ${p}_{r}(\rho )\approx {c}_{s}^{2}\left(\rho -{\rho }_{{\rm{s}}}\right)$, in the radial direction, with ${c}_{s}=c/\sqrt{3}$ and a surface density ρs slightly above the nuclear saturation density ρnuc = 2.7 × 1014 g cm–3. The corresponding mass-radius diagram is in agreement with our estimated value of the radius and with astrophysical observations of other pulsars at 68% confidence level.
Abstract Copyright:
© 2023. The Author(s). Published by the American Astronomical Society.
Journal keyword(s):
Massive stars - Millisecond pulsars - Neutron star cores - Non-standard theories of gravity - Stellar structures
Simbad objects:
11
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