Milone, Antonino; Piotto, G; Bedin, L R; Cassisi, S; Anderson, Jay; Marino, Anna; Pietrinferni, A; Aparcio, A
High-precision HST photometry has revealed that the globular cluster (GC) NGC 2808 hosts a triple main sequence (MS) corresponding to three stellar populations with different helium abundances. We carried out photometry on ACS/WFC HST images of NGC 2808 with the main purpose of measuring the luminosity function (LF) of stars in the three different MSs, and the binary fraction in the cluster. We used isochrones to transform the observed LFs into mass functions (MFs). We estimate that the...[Show more]
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