Buchdahl limit of compact stars in presence of Weyl anomaly

Abstract

We setup an anisotropic compact star model in presence of Weyl ``trace" anomaly. We derive an exact interior solution which determines the contribution of the vacuum trace anomaly. We introduce a dimentionless parameter, $\beta$, to characterize this contribution. Applying appropriate matching conditions with the exterior solution, we determine the model parameters in terms of the Weyl anomaly parameter $\beta$ and the compactness parameter, $C=\frac{2GM}{c^2\mathcal{R}}$ where $M$ and $\mathcal{R}$ are the mass and the radius of the star. We investigate the parameter space $\{\beta ,C\}$ and the corresponding modifications of Buchdahl limit on the maximum compactness. We use astrophysical observations of mass and radius of the pulsar PSR J0740+6620 to constrain the Weyl anomaly parameter $\beta$. Also, we investigate the Mass-Radius diagram with other observational constraints from NICER and LIGO/Virgo collaboration.

9 pages, 3 figures, will appear in PLB

References in corpus (11)

• A NICER View of the Nearest and Brightest Millisecond Pulsar: PSR J0437$\unicode{x2013}$4715
• An updated mass-radius analysis of the 2017-2018 NICER data set of PSR J0030+0451
• The Radius of the High-mass Pulsar PSR J0740+6620 with 3.6 yr of NICER Data
• Strongly interacting matter exhibits deconfined behavior in massive neutron stars
• Trace anomaly as signature of conformality in neutron stars
• Thermodynamics of Conformal Anomaly Corrected Black Holes in AdS Space
• A light strange star in the remnant HESS J1731-347: minimal consistency checks
• Impact of Rastall gravity on mass, radius and sound speed of the pulsar PSR J0740+6620
• Compactness bounds in General Relativity
• Implications of the Conformal Constraint on Sound Speed on the Radius of PSR J0952-0607 within Rastall Gravity
• Quadratic Rastall Gravity: from low-mass HESS J1731-347 to high-mass PSR J0952-0607 pulsars