We have used a set of archived Hubble Space Telescope Advanced Camera for Surveys images to probe the evolved populations of the globular cluster 47 Tucanae. We find an excess of asymptotic giant branch (AGB) stars in the cluster core. We interpret this feature as the signature of an extrapopulation likely made by the progeny of massive stars originated by the evolution of binary systems. Indeed, the comparison with theoretical tracks suggests that the AGB population of 47 Tuc can be significantly contaminated by more massive stars currently experiencing the first ascending red giant branch.
Beccari G., Ferraro F. R., Lanzoni B., Bellazzini M. (2006). A Population of Binaries in the Asymptotic Giant Branch of 47 Tucanae?. THE ASTROPHYSICAL JOURNAL, 652, L121-L124 [10.1086/510019].
A Population of Binaries in the Asymptotic Giant Branch of 47 Tucanae?
FERRARO, FRANCESCO ROSARIO;LANZONI, BARBARA;
2006
Abstract
We have used a set of archived Hubble Space Telescope Advanced Camera for Surveys images to probe the evolved populations of the globular cluster 47 Tucanae. We find an excess of asymptotic giant branch (AGB) stars in the cluster core. We interpret this feature as the signature of an extrapopulation likely made by the progeny of massive stars originated by the evolution of binary systems. Indeed, the comparison with theoretical tracks suggests that the AGB population of 47 Tuc can be significantly contaminated by more massive stars currently experiencing the first ascending red giant branch.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
