STScI Preprint #1288

Some Characteristics of Current Star Formation in the 30 Doradus Nebula Revealed by HST/NICMOS

This paper is dedicated to W.W. Morgan, who taught me the power of morphology to uncover new phenomena in astronomy-NRW.
Based on observations with the NASA/ESA Hubble Space Telescope obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.

The extensive "second generation" of star formation within the 30 Doradus Nebula, evidently triggered by the R136 central cluster around its periphery, has been imaged with HST/NICMOS. Many new IR sources, including multiple systems, clusters, and nebular structures, are found in these images. Six of the NICMOS fields are described here, in comparison with the WFPC2 images of the same fields. Knots 1-3 of Walborn & Blades (early O stars embedded in dense nebular knots) are all found to be compact multiple systems. Knot 1 is shown to reside at the top of a massive dust pillar oriented directly toward R136, whose summit has just been removed, exposing the newborn 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 interpreted 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 also in this field. These outflows from young massive stars in 30 Dor are the first extragalactic examples of the phenomenon. In the field of the pillars 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 investigate the formation and very early evolution of massive stars and multiple systems. The theme of triggered formation within the heads of extensive dust pillars oriented toward R136 is strong. In addition, these results provide further insights into the global structure and evolution of 30 Doradus, which are significant in view of its status as the best resolved extragalactic starburst.

Status:

Appeared in: Astronomical Journal, 117:225:237, 1999 January

Affiliations:

¹) Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
²) Jet Propulsion Laboratory/Infrared Processing, Analysis Center, California Institute of Technology, 770 South Wilson Avenue, Pasadena, California 91125
³) Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago, Chile
⁴) Lick Observatory, University of California, Santa Cruz, California 95064
⁵) Cerro Tololo Inter-American Observatory, National Optical Astronomy Observatories, Casilla 603, La Serena, Chile