The Rotation of the Globular Cluster 47 Tucanae in the Plane of the Sky

Abstract

We have used the Hubble Space Telescope (HST) to measure the component of rotation of 47 Tuc in the plane of the sky, using background stars of the SMC as a reference. The rotation is comparable to that in the line of sight, showing that the axis of rotation of the cluster is considerably inclined. We also give an improved value of the absolute proper motion of 47 Tuc.

Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555.