CCD photometry of the outer halo clusters Pal 4 and NGC 2419.
Abstract
CCD photometry of two outer halo globular clusters, Pal 4 and NGC 2419, has been obtained to sample the stellar population to V = 25 mag. The color-magnitude diagram of Pal 4, when compared to both other globular clusters and theoretical isochrones suggest that this object is a moderately metal poor cluster with [Fe/H] ≡ -1.7 with (m-M)0 = 20.1, and E(B-V) = 0.02 mag. The age of the cluster appears to be ≡15 Gyr, but the cluster does exhibit the red horizontal branch and distinct asymptotic giant branch typical of "second parameter" clusters. Alternatively NGC 2419 appears to be a close analog to M15, with (m-M)0 = 20.0, and E(B-V) = 0.12.
- Publication:
-
European Southern Observatory Conference and Workshop Proceedings
- Pub Date:
- 1987
- Bibcode:
- 1987ESOC...27..381C
- Keywords:
-
- Astronomical Photometry;
- Charge Coupled Devices;
- Globular Clusters;
- Halos;
- Asymptotic Giant Branch Stars;
- Color-Magnitude Diagram;
- Horizontal Branch Stars;
- Metallicity;
- Star Distribution;
- Astrophysics;
- C-M Diagrams:Globular Clusters;
- CCD Photometry:Globular Clusters;
- Distances:Globular Clusters;
- Globular Clusters:Ages;
- Globular Clusters:C-M Diagrams;
- Globular Clusters:CCD Photometry;
- Globular Clusters:Distances;
- Globular Clusters:Metal Content;
- Metal Content:Globular Clusters