AI 中文总结
该研究利用IGRINS - 2仪器获取BD + 44 493的光谱，通过测量原子吸收特征等效宽度并与合成模型比较得出元素丰度新估计值，首次在H波段测到弱原子碳吸收特征，证实其为第二代恒星，证明IGRINS - 2可用于研究低金属性恒星。
AI 中文摘要
我们展示了使用双子北望远镜上新启用的IGRINS - 2仪器获得的BD + 44 493的高分辨率（R~45,000）、高信噪比（S/N>200）的H和K波段光谱。BD + 44 493是一颗著名的碳增强（CEMP; [C/Fe]=+1.40）超贫金属（UMP; [Fe/H]~ - 4.0）恒星。通过测量原子吸收特征的等效宽度并与合成模型比较，得出C、Mg、Si和Ca丰度的新估计值。首次在UMP恒星的H波段测量到弱原子碳吸收特征（C I），其丰度估计与光学波段从CH分子得出的值吻合良好，其他元素丰度值也与先前估计相符，证实其为第二代恒星。这些数据表明IGRINS - 2是研究银河系及其他星系中低金属性恒星的有力新资源。
英文摘要
We present high-resolution (R~45,000), high signal-to-noise (S/N>200) H and K-band spectra of BD+44 493, obtained with the newly commissioned IGRINS-2 instrument on the Gemini North Telescope. BD+44 493 is a well-known carbon-enhanced (CEMP; [C/Fe]=+1.40) ultra metal-poor (UMP; [Fe/H]~-4.0) star that has been extensively studied with high-resolution spectroscopy from the ultraviolet to the infrared. From the IGRINS-2 data, we derive new estimates of the abundances of C, Mg, Si, and Ca by measuring the equivalent widths of several atomic absorption features and comparing the values and line profiles with synthetic models. We measure, for the first time, a weak atomic carbon absorption feature (C I) in a UMP star in the H-band. Our estimated abundance agrees well with other values derived from CH molecules in the optical. The abundance values for the other elements are also in good agreement with previous estimates derived from ultraviolet, optical, and near-infrared observations, confirming the speculations that BD+44 493 is a bona fide second-generation star. With these data, we demonstrate that IGRINS-2 is a powerful new resource for studying and characterizing low-metallicity stars in the Milky Way and beyond.
Comments15 pages, 4 figures, accepted for publication on AJ
