Wolf-Rayet stars in NGC 6822 and IC 1613.
Abstract
Using CCD exposures through interference filters, Wolf-Rayet stars in the Local Group irregular galaxies IC 1613 and NGC 6822 are examined. Twelve W-R candidates in NGC 6822, of which seven are extremely probable, and eight candidates in IC 1613, of which five are extremely probable, are identified by using crowded-field point-spread-function algorithms. Spectral types (WC or WN) are assigned by comparing the magnitude differences measured between the WC and WN frames with that expected for Galactic and LMC stars. NGC 6822 is found to resemble the SMC in its surface density and type of W-R stars, while IC 1613 is quite similar to the LMC. It is concluded that since the LMC and NGC 6822 are most alike in the metallicity of their H II regions and the SMC and IC 1613 are more metal-poor, the LMC must have an approximately 3-times higher density massive-star population than NGC 6822.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- April 1985
- DOI:
- 10.1086/163107
- Bibcode:
- 1985ApJ...291..685A
- Keywords:
-
- Galaxies;
- Local Group (Astronomy);
- Wolf-Rayet Stars;
- Astronomical Photography;
- Bandpass Filters;
- Charge Coupled Devices;
- H Ii Regions;
- Magellanic Clouds;
- Point Spread Functions;
- Stellar Magnitude;
- Astrophysics