Stars are the most fundamental building blocks (in practical scale) in the universe. Without proper understanding on them, one cannot expect to accurately understand the evolution of galaxies. Prof. Yi constructs stellar models from the pre-main-sequence to the white dwarf stage (He is currently in the Yale-Yonsei Isochrone team). Isochrones are currently the best tools for measuring the ages of star clusters and fundamental building blocks for galaxy population synthesis. Particularly, isochrones matches the observed data with high accuracy.

    We have lately updated the Yale Isochrones. Because this new version is much superior to the old ones (Yale Isochrones 1996) that used to be available from this web site, we have decided to remove them from this directory. Instead, check out the new Y2(Yonsei-Yale) ISOCHRONES.

    You can also get an information about horizontal branch evolution.
Check this site.