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

TY - JOUR

T1 - Characterization of Low-mass K2 Planet Hosts Using Near-infrared Spectroscopy

AU - Martinez, Romy Rodriguez

AU - Ballard, Sarah

AU - Mayo, Andrew

AU - Vanderburg, Andrew

AU - Montet, Benjamin T.

AU - Christiansen, Jessie L.

PY - 2019/9

Y1 - 2019/9

N2 - 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 o-, luminosities of, 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.

AB - 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 o-, luminosities of, 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.

KW - planetary systems

KW - planets and satellites: fundamental parameters

KW - stars: fundamental parameters

KW - stars: late-type

KW - stars: low-mass

KW - techniques: spectroscopic

U2 - 10.3847/1538-3881/ab3347

DO - 10.3847/1538-3881/ab3347

M3 - Journal article

SN - 0004-6256

VL - 158

JO - The Astronomical Journal

JF - The Astronomical Journal

IS - 3

ER -