Stellar and Planetary Parameters for K2 's Late-type Dwarf Systems from C1 to C5
- Department of Astronomy, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182 (United States)
- Lunar and Planetary Laboratory, University of Arizona, 1629 E. University Blvd, Tucson, AZ 85721 (United States)
- NASA Ames Research Center, Moffett Field, CA 94035 (United States)
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States)
- Max Planck Institut für Astronomie, Heidelberg (Germany)
- Department of Astronomy, Graduate School of Science, The University of Tokyo, 7-3-1 Bunkyo-ku, Tokyo 113-0033 (Japan)
- Department of Astronomy, Stockholm University, SE-106 91 Stockholm (Sweden)
- NASA Exoplanet Science Institute, California Institute of Technology, Pasadena, CA 91125 (United States)
- Department of Physics and Astronomy, Georgia State University, 25 Park Pl NE #605, Atlanta, GA 30303 (United States)
- Institute for Astronomy, University of Hawai’i at Mānoa, 2680 Woodlawn Dr., Honolulu, HI 96822 (United States)
- Steward Observatory, University of Arizona, 933 N. Cherry Ave, Tucson, AZ 85719 (United States)
- Department of Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States)
- Jet Propulsion Laboratory, 4800 Oak Grove Dr., Pasadena, CA 91109 (United States)
The NASA K2 mission uses photometry to find planets transiting stars of various types. M dwarfs are of high interest since they host more short-period planets than any other type of main-sequence star and transiting planets around M dwarfs have deeper transits compared to other main-sequence stars. In this paper, we present stellar parameters from K and M dwarfs hosting transiting planet candidates discovered by our team. Using the SOFI spectrograph on the European Southern Observatory’s New Technology Telescope, we obtained R ≈ 1000 J -, H -, and K -band (0.95–2.52 μ m) spectra of 34 late-type K2 planet and candidate planet host systems and 12 bright K4–M5 dwarfs with interferometrically measured radii and effective temperatures. Out of our 34 late-type K2 targets, we identify 27 of these stars as M dwarfs. We measure equivalent widths of spectral features, derive calibration relations using stars with interferometric measurements, and estimate stellar radii, effective temperatures, masses, and luminosities for the K2 planet hosts. Our calibrations provide radii and temperatures with median uncertainties of 0.059 R {sub ⊙} (16.09%) and 160 K (4.33%), respectively. We then reassess the radii and equilibrium temperatures of known and candidate planets based on our spectroscopically derived stellar parameters. Since a planet’s radius and equilibrium temperature depend on the parameters of its host star, our study provides more precise planetary parameters for planets and candidates orbiting late-type stars observed with K2 . We find a median planet radius and an equilibrium temperature of approximately 3 R {sub ⊕} and 500 K, respectively, with several systems (K2-18b and K2-72e) receiving near-Earth-like levels of incident irradiation.
- OSTI ID:
- 22661318
- Journal Information:
- Astrophysical Journal, Vol. 837, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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