Variable Stars in Metal-Rich Globular Clusters. II. NGC 6316

Abstract

We present time-series VI photometry of the metal-rich globular cluster NGC 6316. Our color-magnitude diagrams show a predominantly red-clump horizontal branch morphology with no evidence of the blue extensions seen in NGC 6388 and NGC 6441. Our data are in good agreement with published estimates of the reddening and metallicity provided the cluster has an absolute distance modulus of 15.50 mag. We have discovered more than one dozen long-period variable stars in our field of view, and argue that at least seven of them are members of NGC 6316. We have also discovered four RR Lyrae variables, although only one of them probably belongs to the cluster. The specific frequency of RR Lyrae stars in NGC 6316 is found to be less than 0.4, making it clear that this cluster is a normal, metal-rich globular and is not an analog of NGC 6388 and NGC 6441. We recommend long-term photometric monitoring of NGC 6316 to clarify the nature of the RR Lyrae member candidate as well as the pulsation classes of the long-period variables.

arXiv comment33 pages, 5 figures, 6 tables. Accepted for publication in the Astronomical Journal

References in corpus (8)

• Variable Stars in Galactic Globular Clusters
• Discovery of Extended Blue Horizontal Branches in Two Metal-Rich Globular Clusters
• The Second-Parameter Effect in Metal-Rich Globular Clusters
• Variable Stars in the Unusual, Metal-Rich Globular Cluster NGC 6388
• The Variable Stars and Blue Horizontal Branch of the Metal-Rich Globular Cluster NGC 6441
• Variable Stars in the Unusual, Metal-Rich Globular Cluster NGC 6441
• On the observational properties of He-burning stars: some clues on the tilt of the HB in metal rich clusters
• Long Period Variables in Globular Clusters and the Galactic Bulge: Their Dependence on Metallicity

Cited by in corpus (7)

• Accurate distances to Galactic globular clusters through a combination of Gaia EDR3, HST and literature data
• A Comprehensive Catalogue of Variable Stars in the field of 47 Tucanae
• Absolute V-band magnitudes and mass-to-light ratios of Galactic globular clusters
• New LZ and PW(Z) relations of RR Lyrae stars calibrated with Gaia EDR3 parallaxes
• A New Absolute Magnitude Calibration for Red Clump Stars
• VR CCD photometry of variable stars in globular cluster NGC 4147
• Variable Stars in Metal-Rich Globular Clusters. IV. Long Period Variables in NGC 6496