S255‐2: The Formation of a Stellar Cluster

Open Access
Publisher Website
Google Scholar
Abstract
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 μm), H (1.65 μm), K (2.23 μm), and at 3.3 μm. We have also obtained images in the Brγ and Brα hydrogen recombination lines, in the H2, v = 1 → 0 S(1) line, and in the 3.29 μm dust feature emission band. The region consists of a circular core of stars and young stellar objects, as well as nebulosity, and a more diffuse stellar cluster. The Brackett-line emission from the region is at least a factor of 10 greater than the value estimated from the radio continuum flux density, assuming case B recombination. The strongest Brα line emission object is IRS 1b, which appears to be an ionizing wind source. The central core region contains a narrow band of Brγ and H2 emission that we postulate is an ionized jet. The 3.29 μm and the H2 emission are found in a bubble-like region that overlaps and extends beyond the Brα and Brγ emission into the photodissociation region. S255-2 appears to be a young cluster of stars still in the process of forming.

This publication has 27 references indexed in Scilit: