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  • Elemental Abundances of nea...
    Ishikawa, Hiroyuki Tako; Aoki, Wako; Hirano, Teruyuki; Kotani, Takayuki; Kuzuhara, Masayuki; Omiya, Masashi; Hori, Yasunori; Kokubo, Eiichiro; Kudo, Tomoyuki; Kurokawa, Takashi; Kusakabe, Nobuhiko; Narita, Norio; Nishikawa, Jun; Ogihara, Masahiro; Ueda, Akitoshi; Currie, Thayne; Henning, Thomas; Kasagi, Yui; Kolecki, Jared R.; Kwon, Jungmi; Machida, Masahiro N.; McElwain, Michael W.; Nakagawa, Takao; Vievard, Sebastien; Wang, Ji; Tamura, Motohide; Sato, Bun’ei

    The Astronomical journal, 02/2022, Letnik: 163, Številka: 2
    Journal Article

    Abstract 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.