Abstract
We present a study of 21 young star clusters aiming to characterize their association to dense clouds. The structure of the clouds was evaluated by means of the Q statistical fractal analysis, designed to compare their geometric structure with the spatial distribution of the cluster members. The sample was selected from the study by Santos-Silva and Gregorio-Hetem (2012, A&A, 547, A107) that evaluated the radial density profile of the stellar superficial distribution of the young clusters. The fractal dimension and other statistical parameters of most of the sample indicate that there is a good cloud-cluster correlation, when compared to other works based on an artificial distribution of points (Lomax et al. 2011, MNRAS, 412, 627). As presented in a previous work (Fernandes et al. 2012, A&A, 541, A95 ), the cluster NGC 6530 is the only object of our sample that presents anomalous statistical behaviour. The fractal analysis shows that this cluster has a centrally concentrated distribution of stars that differs from the substructures found in the density distribution of the cloud projected in the A_{V} map, suggesting that the original cloud geometry was changed by the cluster formation.
