As part of an ongoing study of high-mass star formation regions, we have imaged the S255-2 triple H II region in near-infrared broadband wavelength bands J (1.23 km), H (1.65 km), K (2.23 km), and at 3.3 km. We have also obtained images in the Brc and Bra hydrogen recombination lines, in the H 2 , v \ 1 ] 0 S(1) line, and in the 3.29 km dust feature emission band. The region consists of a circular core of stars and young stellar objects, as well as nebulosity, and a more di use stellar cluster. The Brackettline emission from the region is at least a factor of 10 greater than the value estimated from the radio continuum ux density, assuming case B recombination. The strongest Bra line emission object is IRS 1b, which appears to be an ionizing wind source. The central core region contains a narrow band of Brc and emission that we postulate is an ionized jet. The 3.29 km and the emission are found in a H 2 H 2 bubble-like region that overlaps and extends beyond the Bra and Brc emission into the photodissociation region. S255-2 appears to be a young cluster of stars still in the process of forming.
Authors: Eric Howard, J. L. Pipher, W. J. Forrest
DOI: https://doi.org/10.1086/304046
Publish Year: 1997
