Characterization of Low-mass K2 Planet Hosts Using Near-infrared Spectroscopy

Research output: Contribution to journalJournal article – Annual report year: 2019Researchpeer-review


  • Author: Martínez, Romy Rodríguez

    Ohio State University, United States

  • Author: Ballard, Sarah

    Massachusetts Institute of Technology, United States

  • Author: Mayo, Andrew

    Astrophysics and Atmospheric Physics, National Space Institute, Technical University of Denmark, Elektrovej, 2800, Kgs. Lyngby, Denmark

  • Author: Vanderburg, Andrew

    University of Texas at Austin, United States

  • Author: Montet, Benjamin T.

    University of Chicago, United States

  • Author: Christiansen, Jessie L.

    California Institute of Technology, United States

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We present moderate resolution near-infrared spectra in the H, J, and K band of M-dwarf hosts to candidate transiting exoplanets discovered by NASA’s K2 mission. We employ known empirical relationships between spectral features and physical stellar properties to measure the effective temperature, radius, metallicity, and luminosity of our sample. Out of an initial sample of 56 late-type stars in K2, we identify 35 objects as M dwarfs. For that subsample, we derive temperatures ranging from 2870 to 4187 K, radii of 0.09–0.83 R⊙, luminosities of -2.67 < log L/L , < -0.67 and [Fe/H] metallicities between −0.49 and 0.51 dex. We then employ the stellar properties derived from spectra, in tandem with the K2 light curves, to characterize their planets. We report 33 exoplanet candidates with orbital periods ranging from 0.19 to 21.16 days, and median radii and equilibrium temperatures of 2.3 R⊕ and 986 K, respectively. Using planet mass–radius relationships from the literature, we identify seven exoplanets as potentially rocky, although we conclude that probably none reside in the habitable zone of their parent stars.
Original languageEnglish
Article number135
JournalAstrophysical Journal
Issue number4
Number of pages14
Publication statusPublished - 2019
CitationsWeb of Science® Times Cited: No match on DOI

    Research areas

  • Planetary systems, Planets and satellites: fundamental parameters, Stars: fundamental parameters, Stars: late-type, Stars: low-mass, Techniques: spectroscopic

ID: 192244811