The traditional theory of stellar structure and evolution, presuming that stars formed and evolved in isolation, and the effect of rotation is negligible, is now a view of the past. Recent studies based on observations of open/globular clusters in/beyond the Milky Way have revealed that stellar rotation significantly impacts stellar evolution. Stars with/without fast rotation will exhibit different photometric appearances and (possibly) evolve to different tracks. In this presentation, I will introduce the progress of the study of stellar rotation from the view of an observer. I will introduce what studies have made people realize the importance of stellar rotation, and how to determine this impact through further observations. What are the scientific implications if stellar rotation does play such an important role, in terms of the effect of stellar evolution, binary interactions? And what can we do to further address this critical science?

BIO
Chengyuan Li is a professor at the School of Physics and Astronomy, Sun Yat-sen University. His research aims to study stellar structure and evolution by observing star clusters' different stellar populations. Chengyuan Li obtained the Ph.D. degree from Peking University in 2015. He was a project researcher at the Purple Mountain Observatory, Chinese Academy of Sciences. In 2016, he went to Macquarie University in Australia for post-doctoral research. Chengyuan Li joined the School of Physics and Astronomy at SYSU in 2019. He is currently undertaking a general project of the National Natural Science Foundation of China (NSFC), and participates in two projects of the National Natural Science Foundation of China (a key project and a youth project).