1999/12/28 by Chisato Ikuta, C. Ikuta, N. Arimoto +2
Physics and Astronomy · #Astro and Planetary Science #Astrophysics (astro-ph) #FOS: Physical sciences #Gamma-ray bursts and supernovae #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/9912526
35 pages, 9 figures. Accepted for publication in A&A, Main Journal
arxiv created 1999/12/28 · openalex publication_date 1999/12/28 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The origin of abundance spreads observed in omega Centauri is studied in the context of the self-enrichment scenario. Five chemical evolution models are constructed and are compared with empirical metallicity distribution of ω Cen. After a series of simulations, it is found that neither of closed-box, outflow, nor infall models can reproduce the empirical metallicity distribution of omega Cen, while a modified outflow model with a bimodal initial mass function (IMF) gives a metallicity distribution that fits closely to the empirical ones. In the modified outflow model, long-lived stars are assumed to form after the first explosion of type II supernovae (SNII) in a proto-cloud. The modified outflow model involves gas infall at the very first chemical evolution. Thus we conclude that self-enrichment causes the abundance dispersion in omega Cen. A success of the outflow model with the bimodal IMF implies that low mass stars in a globular cluster (GC) should have formed in the gas already enriched by the first generation of SNII. This scenario, originally proposed by Cayrel (1986), can explain a lack of globular clusters with [Fe/H] > -2.2 in the Milky Way Galaxy.