The Hubble Space Telescope UV legacy survey of galactic globular clusters - X. The radial distribution of stellar populations in NGC2808

M. Simioni*, A. P. Milone, L. R. Bedin, A. Aparicio, G. Piotto, E. Vesperini, J. Hong

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    37 Citations (Scopus)

    Abstract

    Due to their extreme helium abundance, the multiple stellar populations of the globular cluster NGC 2808 have been widely investigated from a photometric, spectroscopic, and kinematic perspective. The most striking feature of the colour-magnitude diagram of NGC 2808 is the triple main sequence (MS), with the red MS corresponding to a stellar population with primordial helium, and the middle and the blue MS being enhanced in helium up to Y ~ 0.32 and ~0.38, respectively. A recent study has revealed that this massive cluster hosts at least five distinct stellar populations (A, B, C, D, and E). Among them populations A, B, and C correspond to the red MS, while populations C and D are connected to the middle and the blue MS. In this paper, we exploit Hubble Space Telescope photometry to investigate the radial distribution of the red, the middle, and the blue MS from the cluster centre out to about 8.5 arcmin. Our analysis shows that the radial distribution of each of the three MSs is different. In particular, as predicted from multiple-population formation models, both the blue MS and the middle MS appears to be more concentrated than the red MS with a significance level for this result which is above 3σ.

    Original languageEnglish
    Pages (from-to)449-458
    Number of pages10
    JournalMonthly Notices of the Royal Astronomical Society
    Volume463
    Issue number1
    DOIs
    Publication statusPublished - 21 Nov 2016

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