A Measurement of Diffusion in 47 Tucanae

Publication Type
Journal Article
Year of Publication
Jeremy Heyl
Harvey B. Richer
Antolini, Elisa
Ryan Goldsbury
Kalirai, Jason
Parada, Javiera
Pier-Emmanuel Tremblay
Name of Publication
The Astrophysical Journal
Date Published
May 1, 2015
ISBN Number
globular clusters: individual: 47 Tuc; Hertzsprung–Russell and C–M diagrams; stars: kinematics and dynamics; stars: Population II

Using images from the Hubble Space Telescope Wide-Field Camera 3, wemeasure the rate of diffusion of stars through the core of the globularcluster 47 Tucanae (47 Tuc) using a sample of young white dwarfs thatwere identified in these observations. This is the first directmeasurement of diffusion due to gravitational relaxation. We find thatthe diffusion rate κ ≈ 10-13 arcsec2Myr-1 is consistent with theoretical estimates of therelaxation time in the core of 47 Tuc of about 70 Myr.