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arXiv · 1711.04878

Testing the Planet-Metallicity Correlation in M-dwarfs with Gemini GNIRS Spectra

M. J. Hobson·E. Jofré·L. García·R. Petrucci·M. Gómez
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Abstract

While the planet-metallicity correlation for FGK main-sequence stars hosting giant planets is well established, the results are not so clear for M-dwarf stars, for which precise metallicity measurements are not straightforward. However, new techniques using near infrared spectra show promising results. Using these, we determine stellar parameters and metallicities for a sample of 16 M-dwarf stars, 11 of which host planets, with near-infrared spectra from the Gemini Near-Infrared Spectrograph (GNIRS). We find that M-dwarfs with planets are preferentially metal-rich compared to those without planets. This result, based on GNIRS spectra, is supported by the analysis of a relatively larger sample of M stars with planets (18 in total) and a control sample of 213 M stars without known planets, obtained from the catalogue of Terrien et al. (2015). This, on the one hand, coincides with the trend (not only for M- but also for solar-type stars) reported in the literature and, on the other hand, demonstrates the utility of GNIRS spectra to obtain reliable stellar parameters of M stars. We also find that M dwarfs that harbor giant planets are preferentially more metallic than those associated with low-mass planets (Neptune or super-Earth type). This trend also agrees with that previously reported for solar-type stars. These results would favor the core accretion model for planetary formation.

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M. J. Hobson, E. Jofré, L. García, R. Petrucci, M. Gómez. 2017-11-13. Testing the Planet-Metallicity Correlation in M-dwarfs with Gemini GNIRS Spectra. https://arxiv.org/abs/1711.04878

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