Speaker: Dr. Sebastian Kamann (Liverpool John Moores University)

Title: Wempe lecture 3 “Young massive star clusters: Treasure chests of stellar evolution”

Abstract: The colour–magnitude diagrams (CMDs) of star clusters underpin stellar astrophysics. They calibrate stellar evolution models, enable age-dating of stellar populations, and provide templates for interpreting unresolved galaxies. Yet the CMDs of young massive clusters show surprising features, such as split main sequences and extended turn-offs. This raises the question of whether we truly understand the mechanisms governing stellar distributions across the CMD.
In this talk, I will show how binary interactions and stellar rotation reshape CMD morphologies. Using observations of young massive clusters in the Magellanic Clouds obtained with HST and MUSE, we measure the spin velocities of large stellar samples and characterise the clusters’ binary populations. Our results reveal distinct populations of slow and fast rotators occupying different loci in the CMD. The detection of post-interaction binaries, such as blue stragglers and stripped stars, further enables us to constrain population synthesis models and to assess the contribution of massive star clusters to the cosmic rate of compact binary mergers observed via gravitational waves.

• Date:
  May 12, 2026, 2:30 p.m. – 3 p.m.
  
  
• Location:

  AIP; Kirch building, Conference room

  
  
• Contact:
  Peter Weilbacher
  pweilbacher@aip.de