Star clusters and their stellar populations

Stars form in dense molecular cloud clumps, that is, in embedded star clusters. In these they form as binaries or higher-order multiple systems, which are dynamically processed through the dynamical interactions within the dense embedded clusters before the residual gas is expelled from the clusters. Depending on the detailed interests of the PhD student, this project will involve studies of this dynamical processing, of the possible initial distribution functions that define the initial stellar population (multiplicity, stellar initial mass function), the evolution of the embedded clusters into galactic-field populations, the emergence of exotic stellar systems and ejected stars. The tools will be either the Sverre-Aarseth NBody6,7 codes or the Long-Wang PeTaR code, both being used in the research group. The research will be conducted in collaboration with the Nbody, star-cluster and stellar experts in Prague (Drs Jaroslav Haas, Vikrant Jadhav, Dana Korcakova and Ladislav Subr) as well as members of the research group at the University of Bonn (Dr. Jan Pflamm-Altenburg and others). Interested students should have a documented track record of activities related to star clusters and/or computer simulations and be interested to use the Gaia data base. The student will be funded through Charles University and its Astronomical Institute.

Examples of recent research papers:

„Tidal Tails of Nearby Open Clusters. II. A Review of Simulated Properties and the Reliability of Observational Catalogues“ (Jadhav et al. 2025, A&A, in press, 2025arXiv250815056J)
„Are binary-star populations regionally different? In memory of Sverre Aarseth“ (Kroupa, 2025CoSka..55c.217K)
„Mass segregation and velocity dispersion as evidence for a dark star cluster“ (Wu et al., 2019MNRAS.487.4012W)
„The masses of open star clusters and their tidal tails and the stellar initial mass function“ (Wirth et al., 2024A&A…691A.143W)
„Exploring the dynamical evolution of Cepheid multiplicity in star clusters and its implications for B-star multiplicity at birth“ (Dinnbier et al., 2024A&A…690A.385D)
„Dynamical ejections of massive stars from young star clusters under diverse initial conditions“ (Oh & Kroupa, 2016A&A…590A.107O)