Lunch talk on May. 21, 2025

Unlocking massive star formation and evolution mysteries: insights from young open clusters

Speaker: Chen Wang (NJU)

Venue: SWIFAR Building 2111

Time: 12:45 PM, Wednesday, May. 21, 2025

Abstract: 

Massive stars are crucial in our understanding of many areas of modern astrophysics. Despite considerable efforts, there remain numerous unanswered questions regarding the formation and evolution of massive stars. Young star clusters are ideal laboratories to gauge stellar theory, because they are believed to be ensembles of co-eval stars with identical initial chemical compositions. Recent high-precision Hubble Space Telescope (HST) photometry reveals that the main-sequences (MSs) of young star clusters in the color-magnitude diagram are split into several components. This challenges the traditional view of star clusters. By studying these multiple MS components with dense grids of detailed single and binary evolution models, we suggest that stars may predominantly form in close binaries with moderately fast rotation (~50% of critical velocities). Additionally, binary mergers that occurred early on can result in slowly rotating stars. These factors, including stellar natal spins and binary statistics, can have a significant impact on the entire life of stars, from their MS stages to their eventual explosions.