Are nonsingular black holes with super-Planckian hair ruled out by S2 star data?
Mariano Cadoni, Mariafelicia De Laurentis, Ivan De Martino, Riccardo Della Monica, Mauro Oi, Andrea P. Sanna
Abstract
We investigate a nonsingular black hole spacetime representing a strong deformation of the Schwarzschild solution with mass $M$ by an additional hair $\ensuremath{\ell}$, which may be hierarchically larger than the Planck scale. The spacetime is an exact solution of Einstein's equations sourced by an anisotropic fluid. The model presents a de Sitter core and $\mathcal{O}({\ensuremath{\ell}}^{2}/{r}^{2})$ slow-decaying corrections to the Schwarzschild solution. These solutions are thermodynamically preferred when $0.2\ensuremath{\lesssim}\ensuremath{\ell}/GM\ensuremath{\lesssim}0.3$ and are characterized by strong deviations in the orbits of test particles from the Schwarzschild case. In particular, we find corrections to the perihelion precession angle scaling linearly with $\ensuremath{\ell}$. We test our model using the available data for the orbits of the S2 star around ${\text{SgrA}}^{*}$. These data strongly constrain the value of the hair $\ensuremath{\ell}$, casting an upper bound on it of $\ensuremath{\sim}0.47GM$ but do not rule out the possible existence of regular black holes with super-Planckian hair.