The Color‐Magnitude Diagram of the Globular Cluster NGC 6362 and the Canonical Tilt of Horizontal Branches

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Abstract
In this paper we present new and accurate photometry for stars in the Galactic globular cluster NGC 6362. The color-magnitude diagram discloses two peculiarities in the distribution of stars: (1) a slightly tilted horizontal branch (HB) (Δ = 0.1 mag) and (2) a clump of stars near the red edge of the HB. We perform a detailed comparison with theoretical stellar models in both the HB and red giant branch (RGB) phases. It appears that in the moderately metal rich NGC 6362 the tilted HB can be explained as a natural product of canonical evolutionary theories, being a consequence of the minimum in the bolometric correction near 7500 K. We also investigate the effect of decreasing the efficiency of convective transport in stars climbing the RGB. Adopting Z = 0.002 and Y = 0.23, and performing a global fitting with the theoretical isochrones and zero-age HB, an age of 12 ± 1 Gyr is found, together with (m - M)V = 14.68 and E(B-V) = 0.08.