CCD Photometry of NGC 2419
Abstract
CCD photometry of NGC 2419 has been compared to similar data for other metal-poor galactic globular clusters. Although NGC 2419 shares many characteristics with other outer-halo clusters (large tidal and core radius, low central surface brightness), the cluster is atypical of that population in other respects. The object appears to be a close analogy to metal-poor globulars located closer to the galactic center, and in particular the comparison to M15 shows that the color-magnitude diagrams of the two clusters are very similar. The two clusters are very similar in age and metallicity. The predominant difference between M15 and NGC 2419 is that the number of RR Lyraes is significantly smaller in the latter cluster, as well as a lack of an extreme blue tail to the horizontal branch. The observed distance modulus to NGC 2419 appears to be (m-M)V = 20.0±0.15, with a reddening E(B-V) = 0.11±0.05. Comparison to theoretical isochrones suggest the age of the cluster is 16 Gyr and supports the distance modulus found empirically. Oxygen-rich models (Fahlman, Richer, and VanderBerg 1985) and the new Yale models (Green, Demarque, and King 1987) were also examined.
- Publication:
-
The Astronomical Journal
- Pub Date:
- May 1988
- DOI:
- 10.1086/114740
- Bibcode:
- 1988AJ.....95.1422C
- Keywords:
-
- Astronomical Photometry;
- Charge Coupled Devices;
- Color-Magnitude Diagram;
- Galactic Structure;
- Globular Clusters;
- Metallicity;
- Astronomical Catalogs;
- Least Squares Method;
- Astrophysics;
- CLUSTERS: GLOBULAR