A relativistic appearance of hotspots on an ultra-compact dark star

Abstract

We depict the deflection of light near ultra-compact dark energy stars with a photon sphere, drawing inspiration from modern confirmations of general relativity. Utilizing the description of dark energy through a phantom scalar field, we model the spacetime outside the star using an exact dark energy solution metric. We provide a summary of the properties of photon orbits. Additionally, we illustrate the relativistic appearance of a hot spot on the surface of a dark energy star and investigate both the optical appearance of the surface and the star’s visual size on the screen of an asymptotic observer.