光学引力透镜实验。红巨星作为距离指示器
摘要
我们present了红巨星平均I 带亮度与金属丰度的关系。红巨星被提出作为非常有吸引力的标准烛台用于距离确定。该标定基于284颗靠近的红巨星，其高质量光谱允许确定准确的单个金属丰度。高质量的平行坐标（σ_π/π<10%）和光度测量来自Hipparcos数据。金属丰度范围覆盖较大范围：-0.6<[Fe/H]<+0.2 dex。我们发现红巨星平均I 带亮度对金属丰度的弱依赖（约0.13 mag/dex）。更重要的是，Hipparcos样本的金属丰度范围部分与LMC场中的金属丰度重合，从而可能通过直接比较本地Hipparcos红巨星与LMC星系星的亮度来确定LMC距离。对LMC星系 halo 中九个低吸收场的红巨星场光度（在OGLE-II微透镜survey中收集）与Hipparcos红巨星数据进行比较，得到LMC距离模：(m-M)_LMC=18.24±0.08 mag。
引用
@article{arxiv.astro-ph/9910167,
title = {The Optical Gravitational Lensing Experiment. Red Clump Stars as a Distance Indicator},
author = {A. Udalski},
journal= {arXiv preprint arXiv:astro-ph/9910167},
year = {2009}
}
备注
11 pages. Latex+psfig. Accepted for publictation in ApJ Letters. Major revision: 30% larger sample of Hipparcos red giants with spectroscopic metallicities and extended photometry of the LMC field red clump stars (9 lines-of-sight). Due to journal space limitation, sections on comparison of the LMC red clump distance modulus with previous determinations and relations between the color indices and metallicity removed from this version