Interstellar extinction in the open clusters towards galactic longitude around 130 degrees

In this paper we present a detailed study of the intra-cluster reddening material in the young open clusters located around $l \sim 130^o$ using colour-excess diagrams and two-colour diagrams. The study supports the universality of the extinction curves for $\lambda \geq \lambda_J$, 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. 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.

A K Pandey, K Upadhyay, Y Nakada, K Ogura · 2002