A Measurement of Diffusion in 47 Tucanae
Abstract
Using images from the Hubble Space Telescope Wide-Field Camera 3, we measure the rate of diffusion of stars through the core of the globular cluster 47 Tucanae (47 Tuc) using a sample of young white dwarfs that were identified in these observations. This is the first direct measurement of diffusion due to gravitational relaxation. We find that the diffusion rate κ ≈ 10-13 arcsec2 Myr-1 is consistent with theoretical estimates of the relaxation time in the core of 47 Tuc of about 70 Myr.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- May 2015
- DOI:
- 10.1088/0004-637X/804/1/53
- arXiv:
- arXiv:1502.01890
- Bibcode:
- 2015ApJ...804...53H
- Keywords:
-
- globular clusters: individual: 47 Tuc;
- Hertzsprung–Russell and C–M diagrams;
- stars: kinematics and dynamics;
- stars: Population II;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 12 pages, 10 figures, accept for publication in the Astrophysical Journal (added a short passage on blue stragglers descendants and corrected a minor typographical error in Eq. 15)