Infrared Observations of Ongoing Star Formation in the 30 Doradus Nebula and a Comparison with Hubble Space Telescope WFPC 2 Images

Abstract

Intercomparisons of ground-based IR continuum and H_2 images with Hubble Space Telescope WFPC2 images of the 30 Dor Nebula reveal detailed structural relationships, which provide new information about current star formation there. Numerous stellar IR sources have been discovered in or near the bright nebular filaments west and northeast of R136; their locations are intimately connected with the nebular microstructures, as well as with early O stars in dense nebular knots whose optical spectral classifications indicate extreme youth. The H_2 emission predominates in the dust clouds beyond the bright nebulosity and IR sources with respect to R136. The emerging picture suggests that a new stellar generation is being triggered by the energetic activity of the massive central cluster in the remanent interstellar material around its periphery. 30 Dor will likely evolve into a giant shell H ii region similar to N11 in the LMC, containing an older association inside an evacuated central cavity, which is surrounded by H ii regions ionized by a younger population. Such ``two-stage starbursts'' may be characteristic of massive-star formation on this scale. Based in part on observations with the NASA/ESA Hubble Space Telescope, obtained from the data archive at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under NASA contract NAS 5-26555.