Determine the orbital architecture of the Galactic-Center S-stars

Determine whether the S-stars in the Galactic Center are nearly isotropically oriented as predicted by secular evolution driven by the combined stellar torque and Lense–Thirring precession, or instead trace two nearly perpendicular stellar disks whose configuration persists over their lifetimes.

Background

The paper applies its relativistic secular model to the S-cluster surrounding the Galactic-Center supermassive black hole and argues that the combined action of the stellar torque and Lense–Thirring precession can disperse an initially coherent stellar disk into a nearly isotropic distribution of orbital orientations. The authors contrast this interpretation with a result suggesting that the S-stars may instead occupy two nearly perpendicular disks.

Resolving this issue is important because the two possible orbital configurations imply different constraints on the black-hole spin. Persistence of two perpendicular disks would require sufficiently slow Lense–Thirring precession and hence a low spin, whereas an isotropic distribution could be produced by the secular mechanism studied in the paper.