DUST PROPERTIES IN THE DIRECTION OF TRUMPLER-37

The fourteen brightest OB stars of the Trumpler 37 Cluster have been o bserved in the V, R, I, J, H, K photometric bands. These have been use d to derive accurate measurements of the quantity R-V = A(V)/E(B - V). Different from previous studies it is found that < R-V > in Trumpler 37 is close to the mean interstellar value of 3.1. Most of the reddeni ng towards Trumpler 37 is found to be of foreground origin. This is co nsistent with the lack of variations, observed by us, of R-V with the projected distance from the center of the cluster. In two highly redde ned stars of the cluster, whose reddening is certainly mostly local, t he observed R-V is lower than the mean interstellar value of 3.1. This is to be compared with the behaviour of the Trapezium stars in Orion, whose R-V is quite above such value whereas the age of the cluster is similar to the one of Trumpler 37.