Oosterhoff dichotomy
Shen（讨论 | 贡献）2024年9月9日 (一) 09:09的版本 （创建页面，内容为“One of the open problems concerning RRLs is the Oosterhoff dichotomy, namely the sub�division of GGCs into two distinct groups according to the av�erage period < Pab > of their fundamental mode RRL variables (RRab, Oosterhoff 1939). In particular, in some GGCs contain�ing RRLs, < Pab > is about 0.55 days while in others, it is close to 0.65 days, with a period gap between these two groups, named Oosterhoff I (OoI) and Oosterhoff II (OoII), respectively.”）
One of the open problems concerning RRLs is the Oosterhoff dichotomy, namely the sub�division of GGCs into two distinct groups according to the av�erage period < Pab > of their fundamental mode RRL variables (RRab, Oosterhoff 1939). In particular, in some GGCs contain�ing RRLs, < Pab > is about 0.55 days while in others, it is close to 0.65 days, with a period gap between these two groups, named Oosterhoff I (OoI) and Oosterhoff II (OoII), respectively.