Kinematic structure of the Galactic Center S cluster

For 39 of them, orbital elements are known; for the remainder, we know proper motions. The distribution of the inclinations and the proper motion flight directions deviate significantly from a uniform distribution, which one expects if the orientation of the orbits are random.

Across the central arcseconds, the S-cluster stars are arranged in two almost edge-on disks that are located at a position angle approximately +/-45{deg} with respect to the Galactic plane. The angular momentum vectors for stars in each disk point in both directions, i.e., the stars in a given disk rotate in opposite ways. The poles of this structure are located only about 25{deg} from the line of sight.