Some characteristics of current star formation in the 30 Doradus Nebula revealed by HST/NICMOS

The extensive "second generation" of star formation within the 30 Doradus N ebula, evidently triggered by the R136 central cluster around its periphery , has been imaged with the Near-Infrared Camera and Multi-Object Spectromet er (NICMOS) on the Hubble Space Telescope. Many new IR sources, including m ultiple systems, clusters, and nebular structures, are found in these image s. Six of the NICMOS fields are described here, in comparison with the WFPC 2 images of the same fields. Knots 1-3 of Walborn & Blades (early O stars e mbedded in dense nebular knots) are all found to be compact multiple system s. Knot 1 is shown to reside at the top of a massive dust pillar oriented d irectly toward R136, whose summit has just been removed, exposing the newbo rn stellar system. Knots 1 and 3 are also near the brightest IR sources in the region, while parsec-scale jet structures are discovered in association with Knots 2 and 3. The Knot 2 structures consist of detached, nonstellar IR sources aligned on either side of the stellar system, which are interpre ted as impact points of a highly collimated, possibly rotating bipolar jet on the surrounding dark clouds; the H2O maser found by Whiteoak et al. is a lso in this field. These outflows from young massive stars in 30 Dor are th e first extragalactic examples of the phenomenon. In the field of the pilla rs south of R136, recently discussed in comparison with the M16 pillars by Scowen et al., a new luminous stellar IR source has been discovered. These results establish the 30 Doradus Nebula as a prime region in which to inves tigate the formation and very early evolution of massive stars and multiple systems. The theme of triggered formation within the heads of extensive du st pillars oriented toward R136 is strong. In addition, these results provi de further insights into the global structure and evolution of 30 Doradus, which are significant in view of its status as the best resolved extragalac tic starburst.