A MULTIWAVELENGTH STUDY OF STAR-FORMATION IN THE VERY YOUNG OPEN CLUSTER NGC-6530

The distance and formation history of the very young open cluster NGC 6530 were investigated by study ing a total of 132 probable member sta rs of this open cluster. It was concluded that the distance to NGC 653 0 is 1.8 +/- 0.2 kpc, and its interstellar reddening E(B - V) is 0.(m) 30. Furthermore. rye conclude that the extinction law of the intraclus ter material is normal (i.e. R-v = 3.1), but anomalous extinction laws were found for several more embedded stars in the cluster. Of the 132 stars included in this study, 11 are suspected to be variable, five s how Ha in emission and nine show an infrared excess. Among the member stars of NGC 6530, three were found to be part of the Herbig Ae/Be ste llar class, whereas two others are possible members of this stellar gr oup as well. Also, one cluster member is probably a new massive post-A GB star, whereas the same could possibly apply to another member star. Finally, from the distribution of post- and pre-main sequence stars i n the cluster's HR-diagram, it was concluded that the process of star formation in NGC 6530 must have started a few times 10(7) years ago an d, for the less massive stars, is probably still going on today.