HST observations of the LMC compact HII region N11A

We present a study of the LMC compact H II region N11A using Hubble Space Telescope imaging observations which resolve N11A and reveal its unknown nebular and stellar features. The presence of a sharp ionization front extending over more than 4 (1 pc) and fine structure filaments as well as larger loops indicate an environment typical of massive star formation regions, in agreement with high [O III]/H beta line ratios. N11A is a young region, as deduced from its morphology, reddening, and especially high local concentration of dust, as indicated by the Balmer decrement map. Our observations also reveal a cluster of stars lying towards the central part of N11A. Five of the stars are packed in an area less than 2 (0.5 pc), with the most luminous one being a mid O type star. N11A appears to be the most evolved compact Hii region in the Magellanic Clouds so far studied.