The Multiple Stellar Populations in the Ancient LMC Globular Clusters Hodge 11 and NGC 2210

B. CHABOYER; C.K. GILLIGAN; R. WAGNER-KAISER; D. MACKEY; A. SARAJEDINI; J. CUMMINGS; A. GROCHOLSKI; D. GEISLER; R. COHEN; S. VILLANOVA; S-C YANG; M.C. PARISI

Congreso; AAS Meeting #231; 2018

Hubble Space telescope images of the ancient LMC globular clusters Hodge 11 and NGC 2210 in the F336W, F606W and F814W filters were obtained between June 2016 and April 2017. These deep images has been analyzed with the Dolphot software package. High quality photometry has been obtained from three magnitudes brighter than the horizontal branch, to about four magnitudes fainter than the main sequence turn-off. Both clusters show an excess of red main sequence stars in the F336W filter, indicating that multiple stellar populations exist in both clusters. Hodge 11 shows irregularities in its horizontal branch morphology, which is indicative of the presence of an approximately 0.1 dex internal helium abundance spread.