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: http://www.stsci.edu/~kgordon/papers/2011ApJS..193...23M.html
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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 ТБ 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 Я? 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.
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[2011,7][2012,5][2013,3][2014,6][2015,12][2016,1]
Copyright © 2012 Karl D. Gordon All Rights Reserved