Elemental Abundances of nearby M Dwarfs Based on High-resolution Near-infrared Spectra Obtained by the Subaru/IRD Survey: Proof of Concept
Elemental Abundances of nearby M Dwarfs Based on High-resolution Near-infrared Spectra Obtained by the Subaru/IRD Survey: Proof of Concept
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DOI：
10.3847/1538-3881/ac3ee0
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发表时间：
2021-11
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影响因子：
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通讯作者：
H. Ishikawa;W. Aoki;T. Hirano;T. Kotani;M. Kuzuhara;M. Omiya;Y. Hori;E. Kokubo;T. Kudo
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文献类型：
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作者：
H. Ishikawa;W. Aoki;T. Hirano;T. Kotani;M. Kuzuhara;M. Omiya;Y. Hori;E. Kokubo;T. Kudo
对M矮星的详细化学分析很少，但有必要限制周围行星的形成环境和内部结构。本文给出了在Subaru/IRD行星搜索计划中观测到的13 M矮星（2900 < T eff < 3500 K）的元素丰度。它们是中M到晚M矮星，其个别元素的丰度尚未得到很好的研究。我们使用高分辨率（约70，000）近红外（970-1750 nm）光谱，通过基于模型大气的逐线分析，测量Na，Mg，Si，K，Ca，Ti，V，Cr，Mn，Fe和Sr的丰度，典型误差范围从[Fe/H]的0.2 dex到其他[X/H]的0.3-0.4 dex。我们从光谱测量径向速度和联合收割机他们与盖亚天体测量计算银河系的空间速度UVW。由此得到的[Fe/H]值与先前基于中等分辨率K波段光谱的估计一致，显示金属丰度的广泛分布（−0.6 < [Fe/H] < +0.4）。个别元素的丰度比[X/Fe]通常与所有目标中的太阳值一致。虽然[X/Fe]分布与附近的FGK恒星相当，其中大多数属于薄盘族，但最缺乏金属的物体GJ 699可能是厚盘星星。UVW速度也支持这一点。这一结果为利用行星搜寻计划中获得的M矮星近红外光谱掌握附近M矮星的元素丰度变化趋势和银河系恒星星族分布提供了前景。
Detailed chemical analyses of M dwarfs are scarce but necessary to constrain the formation environment and internal structure of planets being found around them. We present elemental abundances of 13 M dwarfs (2900 < T eff < 3500 K) observed in the Subaru/IRD planet search project. They are mid- to late-M dwarfs whose abundance of individual elements has not been well studied. We use the high-resolution (∼70,000) near-infrared (970–1750 nm) spectra to measure the abundances of Na, Mg, Si, K, Ca, Ti, V, Cr, Mn, Fe, and Sr by the line-by-line analysis based on model atmospheres, with typical errors ranging from 0.2 dex for [Fe/H] to 0.3–0.4 dex for other [X/H]. We measure radial velocities from the spectra and combine them with Gaia astrometry to calculate the Galactocentric space velocities UVW. The resulting [Fe/H] values agree with previous estimates based on medium-resolution K-band spectroscopy, showing a wide distribution of metallicity (−0.6 < [Fe/H] < +0.4). The abundance ratios of individual elements [X/Fe] are generally aligned with the solar values in all targets. While the [X/Fe] distributions are comparable to those of nearby FGK stars, most of which belong to the thin-disk population, the most metal-poor object, GJ 699, could be a thick-disk star. The UVW velocities also support this. The results raise the prospect that near-infrared spectra of M dwarfs obtained in the planet search projects can be used to grasp the trend of elemental abundances and the Galactic stellar population of nearby M dwarfs.