PANTERA：I. 利用高分辨率光谱搜寻太阳邻域中金属丰度最高的恒星
PANTERA. I. Hunting for the Most Metal-Rich Stars in the Solar Neighborhood with High-Resolution Spectroscopy
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中文总结 AI 辅助
该研究介绍PANTERA巡天项目，对56颗太阳邻域金属丰度恒星观测后，发现25颗超金属丰度星，其中铁丰度最高达+0.58，并分析Gaia-XP金属丰度的高估问题。
中文摘要 AI 辅助
我们介绍PANTERA（天体物理核合成与金属丰度定向探索项目），这是一项针对太阳邻域金属丰度最高恒星的高分辨率光谱巡天项目。在本首篇论文中，我们报告了56颗金属丰度恒星的铁丰度，这些恒星是从Gaia DR3 XP分光光度金属丰度中选取的。这些目标通过大双筒望远镜（LBT）上的PEPSI光谱仪、自动行星发现者（APF）望远镜上的Levy光谱仪以及凯克望远镜上的HIRES光谱仪进行观测。我们通过铁线的等效宽度分析测量[Fe/H]，有效温度取自测光，表面重力取自Gaia视差。我们利用Gaia基准星验证测量结果，对部分源用多个光谱仪观测、使用第二种合成代码及独立的等效宽度测量方法。我们发现Gaia-XP金属丰度对部分样本的[Fe/H]存在高估：对于矮星，二者结果一致，但选择偏差限制了矮星一致性的表征；对于冷巨星，偏差达0.16±0.02 dex。我们将高估部分归因于冷金属丰度巨星的强蓝色线遮蔽以及XP金属丰度训练所用的巡天标签。我们还发现56颗恒星中有25颗为超金属丰度（[Fe/H]>0.4），其中铁丰度最高的恒星达到[Fe/H]=+0.58。我们讨论了该结果对金属丰度族群研究的意义。
英文摘要
We present PANTERA (Project for Astrophysical Nucleosynthesis and Targeted Exploration of metal-Rich Abundances), a high-resolution spectroscopic survey of the most metal-rich stars in the solar neighborhood. In this first paper, we report iron abundances for 56 metal-rich stars, selected from Gaia DR3 XP spectrophotometric metallicities. These targets were observed with the PEPSI spectrograph on the Large Binocular Telescope (LBT), the Levy spectrograph on the Automated Planet Finder (APF) telescope, and the HIRES spectrograph on the Keck telescope. We measure [Fe/H] from an equivalent-width analysis of iron lines, with the effective temperature taken from photometry and the surface gravity from the Gaia parallax. We verify our measurement using Gaia benchmark stars, observing some sources with more than one spectrograph, using a second synthesis code, and an independent equivalent-width measurement. We find that the Gaia-XP metallicities over-predict [Fe/H] for part of our sample: they are consistent for the dwarfs, though a selection bias limits what the dwarf agreement can show, and reach $0.16\pm0.02$ dex for the cool giants. We attribute the over-prediction in part to the strong blue line blanketing of the cool metal-rich giants and to the survey labels on which the XP metallicities were trained. We also found 25 of the 56 stars to be ultra-metal-rich ([Fe/H] $> 0.4$), with the most iron-rich stars reaching [Fe/H]$=+0.58$. We discuss the implications of our result on studying metal-rich populations.
