Multiple stellar populations in the globular cluster M3 (NGC 5272): a Stromgren perspective

作者：Massari Davide; Lapenna Emilio; Bragaglia Angela; Dalessandro Emanuele; Ramos Rodrigo Contreras; Amigo Pia

来源：Monthly Notices of the Royal Astronomical Society, 2016, 458(4): 4162-4171.

DOI：10.1093/mnras/stw583

• techniques: photometric
• stars: abundances
• Hertzsprung-Russell and colour-magnitude diagrams
• stars: Population II
• globular clusters: general
• globular clusters: individual: ngc5272

We present Stromgren photometry of the Galactic Globular Cluster M3 to study its multiple generations phenomenon. The use of different colour-magnitude diagrams (CMDs) and especially of the notoriously efficient c(y) index allowed us to detect a double red giant branch in the cluster CMD. After decontamination from fore-and background sources, the two sequences turned out to be equally populated. The two components also show a bimodal radial distribution well corresponding to that predicted by numerical simulations for clusters living in an intermediate dynamical evolutive state and with a population with modified chemical composition that was born more centrally concentrated than the primordial. The analysis of high-resolution spectra quantitatively demonstrates that the two detected sequences correspond to the first (Na-poor) generation and the second (Na-rich) generation, thus confirming the importance of synergy between photometry and spectroscopy.

• 出版日期2016-6-1