The dynamical evolution of fractal star clusters: the survival of substructure
نویسندگان
چکیده
We simulate the dynamics of fractal star clusters, in order to investigate the evolution of substructure in recently formed clusters. The velocity dispersion is found to be the key parameter determining the survival of substructure. In clusters with a low initial velocity dispersion, the ensuing collapse of the cluster tends to erase substructure, although some substructure may persist beyond the collapse phase. In clusters with virial ratios of 0.5 or higher, initial density substructure survives for several crossing times, in virtually all cases. Even an initially homogeneous cluster can develop substructure, if it is born with coherent velocity
منابع مشابه
Scaling relations in dynamical evolution of star clusters
We have carried out a series of small scale collisional N-body calculations of single-mass star clusters to investigate the dependence of the lifetime of star clusters on their initial parameters. Our models move through an external galaxy potential with a logarithmic density profile and they are limited by a cut-off radius. In order to find scaling relations between the lifetime of star cluste...
متن کاملThe spatial distribution of stars in open clusters
The analysis of the distribution of stars in open clusters may yield important information on the star formation process and early dynamical evolution of stellar clusters. Here we address this issue by systematically characterizing the internal spatial structure of 16 open clusters in the Milky Way spanning a wide range of ages. Cluster stars have been selected from a membership probability ana...
متن کاملDynamical Mass Segregation on a Very Short Timescale
We discuss the observations and theory of star cluster formation to argue that clusters form dynamically cool (subvirial) and with substructure. We then perform an ensemble of simulations of cool, clumpy (fractal) clusters and show that they often dynamically mass segregate on timescales far shorter than expected from simple models. The mass segregation comes about through the production of a s...
متن کاملThe Spatial Evolution of Stellar Structures in the LMC/SMC
We present an analysis of the spatial distribution of various stellar populations within the Large and Small Magellanic Clouds. We use optically selected stellar samples with mean ages between ∼ 9 and ∼ 1000 Myr, and existing stellar cluster catalogues to investigate how stellar structures form and evolve within the LMC/SMC. We use two statistical techniques to study the evolution of structure ...
متن کاملDynamical evolution of star forming regions
We model the dynamical evolution of star forming regions with a wide range of initial properties. We follow the evolution of the regions’ substructure using theQ–parameter, we search for dynamical mass segregation using the ΛMSR technique, and we also quantify the evolution of local density around stars as a function of mass using the ΣLDR method. The amount of dynamical mass segregation measur...
متن کامل