Stellar tidal disruptions in the composite potential of the Milky Way

Abstract

Traditional TDE models assume a purely Keplerian potential dominated by the black hole, neglecting the possible influence of surrounding galactic structures. In this work, we explore a more realistic environment by incorporating both the SMBH at the center of the Milky Way, Sgr A^*, and its nuclear star cluster (NSC), one of the densest known stellar systems. We model the combined gravitational potential using a Dehnen profile for the NSC and compute the resulting mass fallback rate from a disrupted Sun-like star. Our results reveal that while early-time fallback closely follows the canonical t^−5/3 decay, deviations emerge at later times due to the extended mass distribution of the NSC. Specifically, we observe episodes of accretion slowdown and steepening of the light curve at late times, deviating from the typical power-law decay expected in standard TDE models. These findings demonstrate that even modest contributions from the galactic environment can measurably alter the long-term evolution of a TDE, underscoring the importance of incorporating realistic potentials in modeling stellar disruptions in dense galactic centers.