NEW ASTRONOMY, pp.88-97, 2013 (SCI-Expanded)
We present an M-V absolute magnitude calibration including the B - V colour and [Fe/H] metallicity for the red clump stars in the globular and open clusters with a wide range of metallicities: M-V = 0.627(+/- 0.104)(B - V)(0) + 0.046(+/- 0.043)[Fe/H] + 0.262(+/- 0.111). The calibration equation is valid in the ranges 0.42 < (B - V)(0) < 1.20 mag, -1.55 < [Fe/H] < +0.40 dex and 0.43 < M-V < 1.03 mag. We found that the consistencies in the comparisons of the distances estimated from the calibration equation in this study both with the distances obtained from trigonometric parallaxes and spectrophotometric analysis demonstrate that reliable precise absolute magnitudes for the clump giants can be estimated from the calibration formula. (C) 2013 Elsevier B.V. All rights reserved.