Near-Infrared Spectroscopy of the Compact H II Region W51 IRS 2
Abstract
Medium-resolution (R~460) spectra in the K window have been obtained for the compact H II regions W51 IRS 2 East and IRS 2 West. Brγ, He I, three lines of [Fe III], and seven lines of molecular hydrogen (H2) have been detected. The unidentified line at 2.288 μm was also detected with ~2% of the intensity of Brγ. We derive an electron density of ~105-106 cm-3 in both IRS 2 East and IRS 2 West from [Fe III] line ratios. In both regions, observed H2 line ratios indicate that the excitation of H2 is dominated by fluorescence rather than by shocks.
- Publication:
-
The Astronomical Journal
- Pub Date:
- April 2001
- DOI:
- 10.1086/319952
- Bibcode:
- 2001AJ....121.2089O
- Keywords:
-
- ISM: H II Regions;
- Infrared Radiation;
- ISM: Lines and Bands;
- Stars: Formation