| Type |
Journal Article |
| Names |
I. McDonald, M. L. Boyer, J. Th. van Loon, A. A. Zijlstra, J. L. Hora, B. Babler, M. Block, K. Gordon, M. Meade, M. Meixner, K. Misselt, T. Robitaille, M. Sewiło, B. Shiao, B. Whitney |
| Publication |
The Astrophysical Journal Supplement Series |
| Volume |
193 |
| Issue |
2 |
| Pages |
23 |
| Date |
April 1, 2011 |
| URL |
http://adsabs.harvard.edu/abs/2011ApJS..193...23M |
| Library Catalog |
NASA ADS |
| Abstract |
Fundamental parameters and time evolution of mass loss are investigated for post-main-sequence stars in the Galactic globular cluster 47 Tucanae (NGC 104). This is accomplished by fitting spectral energy distributions (SEDs) to existing optical and infrared photometry and spectroscopy, to produce a true Hertzsprung-Russell diagram. We confirm the cluster's distance as d = 4611+213 -200 pc and age as 12 ± 1 Gyr. Horizontal branch models appear to confirm that no more red giant branch mass loss occurs in 47 Tuc than in the more metal-poor ω Centauri, though difficulties arise due to inconsistencies between the models. Using our SEDs, we identify those stars that exhibit infrared excess, finding excess only among the brightest giants: dusty mass loss begins at a luminosity of ~1000 L sun, becoming ubiquitous above L = 2000 L sun. Recent claims of dust production around lower-luminosity giants cannot be reproduced, despite using the same archival Spitzer imagery. |
| Tags |
Infrared: Stars, STARS: AGB AND POST-AGB, circumstellar matter, globular clusters: individual: NGC 104, outflows, stars: mass-loss, stars: winds |