How fast is mass segregation happening in hierarchically formed embedded star clusters?

• Published in: Monthly notices of the Royal Astronomical Society Vol. 472; no. 1; pp. 465 - 474
• Main Authors: Domínguez, R., Fellhauer, M., Blaña, M., Farias, J. P., Dabringhausen, J.
• Format: Journal Article
• Language: English
• Published: London Oxford University Press 01.11.2017
• Subjects: Graph theory; Initial conditions; Massive stars; Star clusters; Stellar evolution; stars: formation; methods: numerical; galaxies: star clusters: general; galaxies: star formation
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1093/mnras/stx1883

Abstract We investigate the evolution of mass segregation in initially substructured young embedded star clusters with two different background potentials mimicking the gas. Our clusters are initially in virial or subvirial global states and have different initial distributions for the most massive stars: randomly placed, initially mass segregated or even inversely segregated. By means of N-body simulation, we follow their evolution for 5 Myr. We measure the mass segregation using the minimum spanning tree method ΛMSR and an equivalent restricted method. Despite this variety of different initial conditions, we find that our stellar distributions almost always settle very fast into a mass segregated and more spherical configuration, suggesting that once we see a spherical or nearly spherical embedded star cluster, we can be sure it is mass segregated no matter what the real initial conditions were. We, furthermore, report under which circumstances this process can be more rapid or delayed, respectively.