The Effect of Star--Disk Interactions on Highly Eccentric Stellar Orbits
  in Active Galactic Nuclei: A Disk Loss Cone and Implications for Stellar
  Tidal Disruption Events
  Galactic center black holes appear to be nearly universally surrounded by
dense stellar clusters. When these black holes go through an active accretion
phase, the multiple components of the accretion disk, stellar cluster, and
black hole system all coexist. We analyze the effect of drag forces on highly
eccentric stellar orbits incurred as stars puncture through the disk plane.
Disk crossings dissipate orbital energy, drawing eccentric stars into more
circular orbits. For high surface density disks, such as those found around
black holes accreting near the Eddington mass accretion limit, the magnitude of
this energy dissipation can be larger than the mean scatterings that stars
receive by two body relaxation. One implication of this is the presence of a
disk "loss cone" for highly eccentric stellar orbits where the dissipation from
disk interaction outweighs scatter via two body relaxation. The disk loss cone
is larger than the tidal disruption loss cone for near-Eddington black hole
accretion rates. Stellar orbits within the disk loss cone are lost from the
overall cluster as stellar orbits are circularized and stars are potentially
ablated by their high-velocity impacts with the disk. We find, however, that
the presence of the disk loss cone has a minimal effect on the overall rate of
stellar tidal disruptions. Stars are still efficiently fed to the black hole
from more-distant stellar orbits that receive large-enough per orbit scatter to
jump over the disk loss cone and end up tidally disrupted.
