American Astronomical Society, Astrophysical Journal Letters, 1(722), p. L18-L22, 2010
DOI: 10.1088/2041-8205/722/1/l18
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We present chemical abundance analysis of a sample of 15 red giant branch (RGB) stars of the globular cluster NGC 1851 distributed along the two RGBs of the (v, v–y) color-magnitude diagram. We determined abundances for C+N+O, Na, α, iron-peak, and s-elements. We found that the two RGB populations significantly differ in their light (N, O, Na) and s-element content. On the other hand, they do not show any significant difference in their α and iron-peak element content. More importantly, the two RGB populations do not show any significant difference in their total C+N+O content. Our results do not support previous hypotheses suggesting that the origins of the two RGBs and the two subgiant branches of the cluster are related to different content of either α (including Ca) or iron-peak elements, or C+N+O abundance, due to a second generation polluted by Type II supernovae.