Determination of fundamental parameters of stars impacts all fields of astrophysics, from galaxy evolution to constraining the internal structure of exoplanets. This paper presents a detailed spectroscopic analysis of Barnard’s star (otherwise known as Gl 699) that compares an exceptionally high-quality (an average signal-to-noise ratio of ∼1000 in the entire domain), high-resolution near-infrared (NIR) spectrum taken with Canada-France-Hawaii Telescope/SPIRou to PHOENIX-ACES stellar atmosphere models. The observed spectrum shows thousands of lines not identified in the models with a similarly large number of lines present in the model but not in the observed data. We also identify several other caveats, such as continuum mismatch, unresolved contamination, and spectral lines significantly shifted from their expected wavelengths; all of these can be a source of bias for the determination of abundance. Out of >10⁴ observed lines in the NIR that could be used for chemical spectroscopy, we identify a short list of a few hundred lines that are reliable. We present a novel method for determining the effective temperature (T _eff) and overall metallicity of slowly rotating M dwarfs that uses several groups of lines as opposed to bulk spectral fitting methods. With this method, we infer T _eff = 3231 ± 21 K for Barnard's star, consistent with the value of 3238 ± 11 K inferred from the interferometric method. We also provide measurements of the abundance of 15 different elements for Barnard's star, including the abundances of four elements (K, O, Y, Th) never reported before for this star. This work emphasizes the need to improve current atmosphere models to fully exploit the NIR domain for chemical spectroscopy analysis.

中文翻译：

---

使用 SPIRou 对巴纳德星进行全面高分辨率化学光谱分析

恒星基本参数的确定影响着天体物理学的所有领域，从星系演化到约束系外行星的内部结构。本文介绍了巴纳德星（也称为 GL 699）的详细光谱分析，比较了异常高质量（整个域中的平均信噪比为 ∼1000）、高分辨率近红外 (NIR) ）使用加拿大-法国-夏威夷望远镜/SPIRou 根据 PHOENIX-ACES 恒星大气模型拍摄的光谱。观察到的光谱显示了模型中未识别的数千条线，而模型中存在类似大量的线，但观察到的数据中则没有。我们还发现了其他一些警告，例如连续谱不匹配、未解决的污染以及光谱线明显偏离预期波长；所有这些都可能成为丰度测定的偏差来源。在 NIR 中观察到的可用于化学光谱的超过 10 ^{4 个}谱线中，我们确定了一个包含数百个可靠谱线的简短列表。我们提出了一种确定有效温度的新方法（时间 _eff）和缓慢旋转的 M 矮星的整体金属丰度，它使用多组线，而不是批量光谱拟合方法。通过这个方法，我们推断时间 _{巴纳德星的eff} = 3231 ± 21 K，与干涉法推断的值3238 ± 11 K一致。我们还提供了巴纳德星 15 种不同元素丰度的测量结果，包括这颗恒星之前从未报道过的四种元素（K、O、Y、Th）的丰度。这项工作强调需要改进当前的大气模型，以充分利用近红外域进行化学光谱分析。