Population II Post-AGB Stars. I. Methodology, Initial Results, and the First Luminosity Function
Researchers built a multi-wavelength catalog of Post-asymptotic giant branch (PAGB) stars across 39 Galactic Globular Clusters to test their use as reliable Population II distance indicators. They classified these stars into different temperature and luminosity groups, found the PAGB luminosity function is centered at log(Lbol/L⊙) = 3.25, and confirmed that most host clusters have a high Horizontal Branch Ratio (HBR).