Oxygen isotopic ratio in open cluster RGB stars: A new method for accurate mass and age estimations
The study uses surface oxygen isotopic ratios (16O/17O) in Red Giant Branch (RGB) stars to create an independent stellar clock for Galactic archaeology. By comparing these ratios to theoretical predictions based on initial mass, the researchers derived accurate ages and initial masses for intermediate-age open clusters like NGC 6819, showing strong agreement with other dating methods.