1999/11/01 by Young‐Wook Lee, Young-Wook Lee, J. M. Joo +9 · 368 citations
Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Blue straggler #Dwarf galaxy #Dwarf spheroidal galaxy #Galaxy #Gamma-ray bursts and supernovae #Globular cluster #Interacting galaxy #Milky Way #Physics #Sagittarius #Star cluster #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1038/46985
published in Nature 402(6757), 55-57 (Nature Portfolio) · 7 pages, 3 figures, Latex+nature.sty (included), To appear in November 4th issue of Nature
openalex publication_date 1999/11/01 · arxiv created 1999/11/09 · arxiv updated 2010/04/06 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
The discovery of the Sagittarius dwarf galaxy, which is being tidally disrupted by and merging with the Milky Way, supports the view that the halo of the Galaxy has been built up at least partially by the accretion of similar dwarf systems. The Sagittarius dwarf contains several distinct populations of stars, and includes M54 as its nucleus, which is the second most massive globular cluster associated with the Milky Way. The most massive globular cluster is omega Centauri, and here we report that omega Centauri also has several distinct stellar populations, as traced by red-giant-branch stars. The most metal-rich red-giant-branch stars are about 2 Gyr younger than the dominant metal-poor component, indicating that omega Centauri was enriched over this timescale. The presence of more than one epoch of star formation in a globular cluster is quite surprising, and suggests that omega Centauri was once part of a more massive system that merged with the Milky Way, as the Sagittarius dwarf galaxy is in the process of doing now. Mergers probably were much more frequent in the early history of the Galaxy and omega Centauri appears to be a relict of this era.