Empirical relationship between calcium triplet equivalent widths and [Fe/H] using Gaia photometry

I present a new empirical relationship for red giant branch stars between the overall metallicity of the star and the sum of equivalent widths of the near-infrared calcium triplet (CaT) spectral lines. This method takes advantage of the all-sky photometry and astrometry of the Gaia mission, and the archival spectra from 2050 red giant branch stars from 18 globular clusters (-0.69&gt;[Fe/H]&gt;-2.44) acquired with the Anglo-Australian Telescope's AAOmega spectrograph. &lt;cluster_name&gt;.tar.gz Raw and reduced spectra for 18 globular clusters (NGC104, NGC6752, NGC6809, NGC288, NGC7099, NGC362, NGC6218, NGC4590, IC4499, NGC1904, ESO452-SC06, ESO280-SC12, NGC1851, NGC6624, NGC2298, Pal 5, NGC5024, Terzan 8, NGC5053) Lists of likely members Measured equivalent widths and radial velocities本研究构建了适用于红巨星支恒星的全新经验关系，关联恒星整体金属丰度与近红外钙三重线（near-infrared calcium triplet, CaT）谱线等效宽度之和。该方法整合利用了盖亚任务（Gaia mission）的全天测光与天体测量数据，以及使用英澳望远镜（Anglo-Australian Telescope）AAOmega光谱仪获取的存档光谱；这些光谱源自18个球状星团的2050颗红巨星支恒星，对应星团的金属丰度[Fe/H]取值范围为-2.44至-0.69。<cluster_name>.tar.gz 包含18个球状星团的原始光谱与归算后光谱，涉及星团包括NGC104、NGC6752、NGC6809、NGC288、NGC7099、NGC362、NGC6218、NGC4590、IC4499、NGC1904、ESO452-SC06、ESO280-SC12、NGC1851、NGC6624、NGC2298、Pal 5、NGC5024、Terzan 8、NGC5053；该压缩包同时提供候选成员星列表、实测等效宽度与径向速度数据。