Mass segregation

About: Mass segregation is a research topic. Over the lifetime, 1024 publications have been published within this topic receiving 57729 citations.

Fragmentation of Young Massive Clusters: A Hybrid Monte Carlo Simulation Study

Abstract: To study the hierarchical fragmentation procedure in Young Massive Clusters, a stochastic model has been developed. Binary fragments along with individual stars are primarily studied in this work. Stellar masses for individual stars have been generated from the univariate truncated Pareto distribution and the stellar masses for binary stars have been generated from the truncated bi-variate Skew Normal Distribution using the Hamiltonian Monte Carlo method. The above distribution is used by observing the fitted bi-variate distribution of masses of all type of binary stars viz. visual binaries, spectroscopic binaries and eclipsing binaries. The resulting mass spectrum computed at different projected distances are observed under opacity limited fragmentation procedure and they display signature of mass segregation along the core to radius, whereas degree of segregation becomes reduced due to inclusion of all type of binary fragments in comparison to inclusion of eclipsing binaries only.

Disintegration of the Aged Open Cluster Berkeley 17

Abstract: We present the analysis of the morphological shape of Berkeley 17, the oldest known open cluster (~10 Gyr), using a probabilistic star counting of Pan-STARRS point sources, and confirm its core-tail shape, plus an antitail, previously detected with the 2MASS data. The stellar population, as diagnosed by the color-magnitude diagram and theoretical isochrones, shows many massive members in the cluster core, whereas there is a paucity of such members in both tails. This manifests mass segregation in this aged star cluster with the low-mass members being stripped away from the system. It has been claimed that Berkeley 17 is associated with an excessive number of blue straggler candidates. Comparison of nearby reference fields indicates that about half of these may be field contamination.

The structures of embedded clusters in the Perseus, Serpens and Ophiuchus molecular clouds

Abstract: The young stellar population data of the Perseus, Ophiuchus and Serpens molecular clouds are obtained from the Spitzer c2d legacy survey in order to investigate the spatial structure of embedded clusters using the nearest neighbour and minimum spanning tree method. We identify the embedded clusters in these clouds as density enhancements and analyse the clustering parameter Q with respect to source luminosity and evolutionary stage. This analysis shows that the older Class 2/3 objects are more centrally condensed than the younger Class 0/1 protostars, indicating that clusters evolve from an initial hierarchical configuration to a centrally condensed one. Only IC348 and the Serpens core, the older clusters in the sample, shows signs of mass segregation (indicated by the dependence of Q on the source magnitude), pointing to a significant effect of dynamical interactions after a few Myr. The structure of a cluster may also be linked to the turbulent energy in the natal cloud as the most centrally condensed cluster is found in the cloud with the lowest Mach number and vice versa. In general these results agree well with theoretical scenarios of star cluster formation by gravoturbulent fragmentation.

The Blue Straggler Star Radial Distribution: Clues on Formation Mechanisms

Abstract: By means of high-resolution (HST) and wide-field (GALEX and ground-based) observations in the UV and optical bands, we have derived the radial distribution of the Blue Stragglers Star population in a number of galactic globular clusters. Monte-Carlo dynamical simulations have been used to interpret the radial distributions and to infer clues on the formation mechanisms of these puzzling stars.