A New Absolute Magnitude Calibration for Red Clump Stars

TL;DR

This paper introduces a new calibration for the absolute magnitude of red clump stars that incorporates colour and metallicity, improving distance estimates for these stars across various clusters.

Contribution

The study provides a novel calibration formula for red clump stars' absolute magnitudes using B-V colour and [Fe/H], valid over a wide parameter range.

Findings

Calibration agrees with trigonometric and spectrophotometric distances.

Reliable absolute magnitudes can be estimated for red clump giants.

Calibration applicable across diverse metallicities and colours.

Abstract

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)o+0.046(0.043)[Fe/H]+0.262(0.111). The calibration equation is valid in the ranges 0.42<(B-V)o<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.