Corrected thermodynamics and radiation predictions of modified black bounce compact objects

Abstract

We study the thermodynamic properties and radiation characteristics of a regular compact object obtained by applying the Simpson–Visser (SV) regularisation to the Schwarzschild modified gravity (MOG) black hole. The resulting SV-MOG spacetime, whose lapse function involves both the MOG coupling parameter

and the black-bounce parameter l , smoothly interpolates between a regular black hole, a one-way wormhole, and a traversable wormhole depending on the parameter l . We derive the Hawking temperature and heat capacity for the black-hole branch, identifying second-order phase transitions signaled by sign changes in

$$C_V$$ C V

, and, for the horizonless wormhole branch – where no causal horizon and hence no genuine Hawking radiation exists – we instead construct a physically well-defined effective temperature from the Lyapunov exponent of the unstable photon sphere. Quantum gravitational corrections to the entropy are incorporated via logarithmic terms parameterized by coefficients

$$\beta _1$$ β 1

,

$$\beta _2$$ β 2

, whose theoretically preferred ranges in loop quantum gravity and string theory we discuss, and we show that deviations from the Bekenstein–Hawking area law become significant at small horizon radii. A linear scalar-perturbation analysis further shows that the effective radial potential remains non-negative throughout the black-hole exterior and across the wormhole throat, indicating no evidence of instability against monopole perturbations, independently of the thermodynamic stability inferred from the heat capacity. For the radiation sector, we compute the electromagnetic flux, effective disk temperature, and spectral luminosity of geometrically thin accretion disks surrounding both black hole and wormhole configurations. Our results demonstrate that increasing

$$\alpha $$ α

enlarges the event horizon and enhances the emission, while increasing l suppresses the horizon and softens the spectral profile, providing observational signatures that may distinguish SV-MOG compact objects from their Schwarzschild and pure SV counterparts.