TY - JOUR
T1 - K2-155
T2 - A Bright Metal-poor M Dwarf with Three Transiting Super-Earths
AU - Hirano, Teruyuki
AU - Dai, Fei
AU - Livingston, John H.
AU - Fujii, Yuka
AU - Cochran, William D.
AU - Endl, Michael
AU - Gandolfi, Davide
AU - Redfield, Seth
AU - Winn, Joshua N.
AU - Guenther, Eike W.
AU - Prieto-Arranz, Jorge
AU - Albrecht, Simon
AU - Barragan, Oscar
AU - Cabrera, Juan
AU - Cauley, P. Wilson
AU - Csizmadia, Szilard
AU - Deeg, Hans
AU - Eigmüller, Philipp
AU - Erikson, Anders
AU - Fridlund, Malcolm
AU - Fukui, Akihiko
AU - Grziwa, Sascha
AU - Hatzes, Artie P.
AU - Korth, Judith
AU - Narita, Norio
AU - Nespral, David
AU - Niraula, Prajwal
AU - Nowak, Grzegorz
AU - Pätzold, Martin
AU - Palle, Enric
AU - Persson, Carina M.
AU - Rauer, Heike
AU - Ribas, Ignasi
AU - Smith, Alexis M.S.
AU - Eylen, Vincent Van
N1 - Funding Information:
This work was supported by Japan Society for Promotion of Science (JSPS) KAKENHI grant No. JP16K17660. D.G. gratefully acknowledges the financial support of the Programma Giovani Ricercatori-Rita Levi Montalcini-Rientro dei Cervelli (2012) awarded by the Italian Ministry of Education, Universities and Research (MIUR). This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No. 730890. This material reflects only the authors views and the Commission is not liable for any use that may be made of the information contained therein. I.R. acknowledges support by the Spanish Ministry of Economy and Competitiveness (MINECO) and the Fondo Europeo de Desarrollo Regional (FEDER) through grant ESP2016-80435-C2-1-R.
Publisher Copyright:
© 2018. The American Astronomical Society. All rights reserved.
PY - 2018/3
Y1 - 2018/3
N2 - We report on the discovery of three transiting super-Earths around K2-155 (EPIC 210897587), a relatively bright early M dwarf (V = 12.81 mag) observed during Campaign 13 of the NASA K2 mission. To characterize the system and validate the planet candidates, we conducted speckle imaging and high-dispersion optical spectroscopy, including radial velocity measurements. Based on the K2 light curve and the spectroscopic characterization of the host star, the planet sizes and orbital periods are 1.55-0.17+0.20R⊕ and 6.34365 ±0.00028 days for the inner planet; 1.95-0.22+0.27R⊕ and 13.85402 ±0.00088 days for the middle planet; and 1.64-0.17+0.18 R⊕ and 40.6835 ±0.0031 days for the outer planet. The outer planet (K2-155d) is near the habitable zone, with an insolation 1.67 ±0.38 times that of the Earth. The planet's radius falls within the range between that of smaller rocky planets and larger gas-rich planets. To assess the habitability of this planet, we present a series of three-dimensional global climate simulations, assuming that K2-155d is tidally locked and has an Earth-like composition and atmosphere. We find that the planet can maintain a moderate surface temperature if the insolation proves to be smaller than ∼1.5 times that of the Earth. Doppler mass measurements, transit spectroscopy, and other follow-up observations should be rewarding, as K2-155 is one of the optically brightest M dwarfs known to harbor transiting planets.
AB - We report on the discovery of three transiting super-Earths around K2-155 (EPIC 210897587), a relatively bright early M dwarf (V = 12.81 mag) observed during Campaign 13 of the NASA K2 mission. To characterize the system and validate the planet candidates, we conducted speckle imaging and high-dispersion optical spectroscopy, including radial velocity measurements. Based on the K2 light curve and the spectroscopic characterization of the host star, the planet sizes and orbital periods are 1.55-0.17+0.20R⊕ and 6.34365 ±0.00028 days for the inner planet; 1.95-0.22+0.27R⊕ and 13.85402 ±0.00088 days for the middle planet; and 1.64-0.17+0.18 R⊕ and 40.6835 ±0.0031 days for the outer planet. The outer planet (K2-155d) is near the habitable zone, with an insolation 1.67 ±0.38 times that of the Earth. The planet's radius falls within the range between that of smaller rocky planets and larger gas-rich planets. To assess the habitability of this planet, we present a series of three-dimensional global climate simulations, assuming that K2-155d is tidally locked and has an Earth-like composition and atmosphere. We find that the planet can maintain a moderate surface temperature if the insolation proves to be smaller than ∼1.5 times that of the Earth. Doppler mass measurements, transit spectroscopy, and other follow-up observations should be rewarding, as K2-155 is one of the optically brightest M dwarfs known to harbor transiting planets.
KW - planets and satellites: detection
KW - stars: individual (K2-155 = EPIC 210897587)
KW - techniques: photometric
KW - techniques: radial velocities
KW - techniques: spectroscopic
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U2 - 10.3847/1538-3881/aaaa6e
DO - 10.3847/1538-3881/aaaa6e
M3 - Article
AN - SCOPUS:85043605959
SN - 0004-6256
VL - 155
JO - Astronomical Journal
JF - Astronomical Journal
IS - 3
M1 - 124
ER -