2003A&A...397..191P

In this paper we present a detailed study of the intra-cluster reddening material in the young open clusters located around l∼130° using colour-excess diagrams and two-colour diagrams. The study supports the universality of the extinction curves for λ≥λ_J, whereas for shorter wavelengths the curve depends upon the value of the R_cluster (total-to-selective absorption in the cluster region). The value of R_cluster in the case of NGC 654, NGC 869 and NGC 884 is found to be normal, whereas the value of R_cluster in the cluster regions NGC 1502 and IC 1805 indicates an anomalous reddening law in these regions. In the case of NGC 1502 the value of R_cluster is found to be lower (2.57±0.27) whereas in the case of IC 1805 it is higher (3.56±0.29) than the normal value of 3.1. Although the intra-cluster material indicates a higher value of R_cluster in the NGC 663 region, the error in the estimation of R_cluster is too large to conclude anything. It is also found that the extinction process in the U band in the case of NGC 663 seems to be less efficient, whereas in the case of NGC 869 the process is more efficient.