IUE OBSERVATIONS OF YOUNG CLUSTERS IN THE LARGE MAGELLANIC CLOUD

We present the results of a study of the ultraviolet properties of the most massive stars in two young clusters in the Large Magellanic Clou d (LMC), NGC 1770 and NGC 2014. Although there is some variation acros s each cluster, we find that the properties of the interstellar extinc tion toward these clusters are consistent with those previously derive d for stars in the Doradus Nebula region of the LMC. Using the IUE spe ctra and Kurucz model atmospheres, we have derived H-R diagrams for bo th clusters and find that: (1) there appear to have been two episodes of massive star formation in NGC 1770, one 4-5 x 10(6) yr ago and the other similar to 10 x 10(6) yr ago; and (2) star formation in NGC 2014 appears to have been relatively coeval (2-5) x 10(6) yr ago. Our anal ysis of the properties of the winds of these stars supports earlier co nclusions that although the terminal velocities of the stellar winds o f these stars scale with the metallicity of the LMC, the mass loss rat es do not.