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

¹ State Observatory, Manora Peak, Naini Tal, 263 129, Uttaranchal, India
² Kiso Observatory, School of Science, University of Tokyo, Mitake-mura, Kiso-gun, Nagano 397-0101, Japan
³ Kokugakuin University, Higashi, Shibuya-ku, Tokyo 150-8440, Japan

Corresponding author: A. K. Pandey, pandey@upso.ernet.in

Received: 26 March 2002
Accepted: 5 September 2002

Abstract

In this paper we present a detailed study of the intra-cluster reddening material in the young open clusters located around using colour-excess diagrams and two-colour diagrams. The study supports the universality of the extinction curves for , 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 whereas in the case of IC 1805 it is higher 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.