RED GIANT BRANCH OF THE METAL POOR GLOBULAR CLUSTERS: I. BUMP, TIP, AND DISTANCE FROM NEAR INERARED PHOTOMETRY

Journal of Astronomy and Space Sciences

Y.-J. Sohn¹  J.-W. Kim¹  A. Kang¹ 

[1] Department of Astronomy, Yonsei University, Seoul 120-749, Korea;

关键词: RGB bump;    RGB tip;    distance;    globular clusters;    near-infrared photometry;   

DOI  :  10.5140/JASS.2006.23.2.091

来源: DOAJ

【 摘 要 】

We use near-infrared observations of eight selected Galactic globular clusters to estimate their distances by comparing the observed and theoretically predicted K magnitudes of the red giant branch bumps and tips. The K magnitude levels of the RGB bump and tip have been measured from the luminosity function of the selected RGB stars in the clusters. Theoretical absolutemagnitudes of the RGB bump and tip are taken from the Yonsei-Yale isochrones. Comparing the observed apparent K magnitude with the derived absolute magnitude, we calculate the distance moduli of the clusters. We discuss the dependency of the derived distance modulus on the cluster age and the uncertainty of the distance measurement from the near-infrared photometry of the RGB bump and tip.

【 授权许可】

Unknown