INFRARED OBSERVATIONS OF ONGOING STAR-FORMATION IN THE 30-DORADUS-NEBULA AND A COMPARISON WITH HUBBLE-SPACE-TELESCOPE WFPC2 IMAGES

Intercomparisons of ground-based IR continuum and H-2 images with Hubb le Space Telescope WFPC2 images of the 30 Dor Nebula reveal detailed s tructural relationships, which provide new information about current s tar formation there. Numerous stellar IR sources have been discovered in or near the bright nebular filaments west and northeast of R136; th eir locations are intimately connected with the nebular microstructure s, as well as with early O stars in dense nebular knots whose optical spectral classifications indicate extreme youth. The H-2 emission pred ominates in the dust clouds beyond the bright nebulosity and IR source s with respect to R136. The emerging picture suggests that a new stell ar generation is being triggered by the energetic activity of the mass ive central cluster in the remanent interstellar material around its p eriphery. 30 Dor will likely evolve into a giant shell H II region sim ilar to N11 in the LMC, containing an older association inside an evac uated central cavity, which is surrounded by H II regions ionized by a younger population. Such ''two-stage starbursts'' may be characterist ic of massive-star formation on this scale.