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Discovery of Carbon/Oxygen depleted Blue Straggler Stars in 47 Tucanae: the chemical signature of a mass-transfer formation process

F. R. Ferraro·E. Sabbi·R. Gratton·G. Piotto·B. Lanzoni·E. Carretta·R. T. Rood·A. Sills·F. Fusi Pecci·S. Moehler·G. Beccari·S. Lucatello·N. Compagni
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Abstract

We use high-resolution spectra obtained with the ESO Very Large Telescope to measure surface abundance patterns of 43 Blue Stragglers stars (BSS) in 47 Tuc. We discovered that a sub-population of BSS shows a significant depletion of Carbon and Oxygen with respect to the dominant population. This evidence would suggest the presence of CNO burning products on the BSS surface coming from a deeply peeled parent star, as expected in the case of mass-transfer process. This is the first detection of a chemical signature clearly pointing to a specific BSS formation process in a globular cluster.

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F. R. Ferraro, E. Sabbi, R. Gratton, G. Piotto, B. Lanzoni, E. Carretta, R. T. Rood, A. Sills, F. Fusi Pecci, S. Moehler, G. Beccari, S. Lucatello, N. Compagni. 2006-10-03. Discovery of Carbon/Oxygen depleted Blue Straggler Stars in 47 Tucanae: the chemical signature of a mass-transfer formation process. https://doi.org/10.1086/507327

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