NGC 3603 and Its Wolf-Rayet Stars: Galactic Clone of R136 at the Core of 30 Doradus, but without the Massive Surrounding Cluster Halo
Abstract
HST/PC images of the dense stellar cluster at the center of the Galaxy's most massive visible H II region, NGC 3603, reveal remarkable similarity to the dense core R136 in the Local Group's most massive Giant H II region, 30 Dor. The projected star density for stars brighter than M_V_ = -5.0 in both objects increases inwards to the last data bin in both objects at r = 0.033 pc with a power-law of slope close to - 1.8. Even the central star density in NGC 3603 is similar to that found in R136. Outside r~ 1 pc, NGC 3603 plummets to zero density, at least for its massive stars, while 30 Dor continues to decrease with similar power- law slope out to r ~ 130 pc. Narrowband He II 4686 A images reveal that NGC 3603 contains three WR stars; they stand out as the brightest members of NGC 3603, all located within the central 0.1 pc. However, while R136 also contains three bright WR stars within 0.1 pc of its center, they are almost a magnitude fainter than NGC 3603's WR stars. Reasons for these differences are probably related to the different environments and ages of the two objects.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- November 1994
- DOI:
- 10.1086/174891
- Bibcode:
- 1994ApJ...436..183M
- Keywords:
-
- Density Measurement;
- H Ii Regions;
- Star Clusters;
- Stellar Mass;
- Hubble Space Telescope;
- Local Group (Astronomy);
- Statistical Distributions;
- Stellar Spectra;
- Wolf-Rayet Stars;
- Astronomy