A Comparison of the Infrared Luminosity and Ionizing Luminosity of Selected Star Forming Regions
Abstract
We have carried out an investigation of the reddest H II regions in the IRAS Point Source Catalog, with the object of determining their stellar content. Of the 24, 13 are observable at the VLA, and the results of observations of twelve are presented in this paper. From this data and other radio data from the literature, as well as estimated distances to the sources, we have calculated the total luminosity of the contained stars from the IRAS data, and plotted this against the total ionization as determined from the radio flux density. These are then compared with the luminosity and ionizing flux expected for Zero Age Main-Sequence stars. Points which lie above Cepheus A could be due chiefly to H II regions which contain multiple stars, while the apparent ionizing flux could be increased by the presence of stellar winds or jets. This approach should enable an estimate to be made of the number of ionizing stars in a radio H II region, allowing determination of the initial mass function. On the other hand, the results could be interpreted in terms of the sources containing stars with excess luminosity and ionizing flux.
- Publication:
-
The Astronomical Journal
- Pub Date:
- April 1993
- DOI:
- 10.1086/116528
- Bibcode:
- 1993AJ....105.1495H
- Keywords:
-
- Brightness Distribution;
- H Ii Regions;
- Infrared Astronomy;
- Ionizing Radiation;
- Star Formation;
- Stellar Luminosity;
- Infrared Astronomy Satellite;
- Mass Distribution;
- Plasma Jets;
- Radio Astronomy;
- Stellar Evolution;
- Stellar Winds;
- Astrophysics;
- ISM: HII REGIONS;
- INFRARED: STARS