We present 2 micron narrow-band images of the core H II region in the Galactic star forming region Sagittarius D. The emission-line images are centered on 2.17 micron (Br gamma ) and 2.06 micron (He I). The H II region appears at the edge of a well defined dark cloud, and the morphology suggests a blister geometry as pointed out in earlier radio continuum work. There is a deficit of stars in general in front of the associated dark cloud indicating the H II region is located in-between the Galactic center and the sun. The lesser spatial extent of the He I line emission relative to Br gamma places the effective temperature of the ionizing radiation field below 40,000 K. The He I 2.06 micron to Br gamma ratio and Br gamma / far infrared dust emission put T_eff at about 36,500 K to 40,000 K as derived from ionization models.
Back to the gcnews home-page.