Accumulated tidal heating of stars over multiple pericentre passages near SgrA

Abstract

We consider the long-term tidal heating of a star by the supermassive black hole at the Galactic centre, SgrA*. We show that gravitational interaction with background stars leads to a linear growth of the tidal excitation energy with the number of pericentre passages near SgrA*. The accumulated heat deposited by excitation of modes within the star over many pericentre passages can lead to a runaway disruption of the star at a pericentre distance that is four to five times farther than the standard tidal disruption radius. The accumulated heating may explain the lack of massive (≳10M⊙) S-stars closer than several tens of au from SgrA*. © 2013 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society.