Multiple Stellar Populations in the Giant Branches of Galactic Globular Clusters

Abstract

In this Chapter, I present the GGC 47 Tucanae’s CMD, which possesses obvious populations anomalies in its SGB and RGB. There is a clearly broadened SGB and RGB in its CMD, the morphology of its giant branches is consistent with the description in Sect. 1.4.1, which can be ideally described as a combination of stellar populations with different ages, helium abundances and metallicities. The broadening in its giant branches is spatially dependent, with the inner part seeming to contain larger fraction of secondary population stars, which strongly indicates different dynamics between first generation and second generation stars. Unlike BSSs, which only occupies a small fraction to population of giant stars, the number of secondary stellar population stars in 47 Tuc is comparable to their first stellar population counterparts.