K2-155: A Bright Metal-poor M Dwarf with Three Transiting Super-Earths
Artikel i vetenskaplig tidskrift, 2018
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 +0.20 R ⊕ and 6.34365 ±0.00028 days for the inner planet; 1.95 -0.22 +0.27 R ⊕ 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.
techniques: spectroscopic
planets and satellites: detection
techniques: photometric
techniques: radial velocities
stars: individual (K2-155 = EPIC 210897587)
Författare
T. Hirano
Tokyo Institute of Technology
Fei Dai
Princeton University
Massachusetts Institute of Technology (MIT)
J.H. Livingston
University of Tokyo
Yuka Fujii
Tokyo Institute of Technology
William D. Cochran
The University of Texas at Austin
M. Endl
The University of Texas at Austin
D. Gandolfi
Universita degli Studi di Torino
S. Redfield
Wesleyan University
N. Joshua
Princeton University
E. W. Guenther
Thüringer Landessternwarte Tautenburg
J. Prieto-Arranz
Universidad de la Laguna
Instituto de Astrofísica de Canarias
Simon Albrecht
Aarhus Universitet
O. Barragán
Universita degli Studi di Torino
J. Cabrera
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
P.W. Cauley
Arizona State University
Szilard Csizmadia
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
H. Deeg
Universidad de la Laguna
Instituto de Astrofísica de Canarias
P. Eigmüller
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
Anders Erikson
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
Malcolm Fridlund
Universiteit Leiden
Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik
A. Fukui
National Astronomical Observatory of Japan
S. Grziwa
Universität zu Köln
A. Hatzes
Thüringer Landessternwarte Tautenburg
Judith Korth
Universität zu Köln
Norio Narita
National Institutes of Natural Sciences
University of Tokyo
National Astronomical Observatory of Japan
David Nespral
Universidad de la Laguna
Instituto de Astrofísica de Canarias
Prajwal Niraula
Wesleyan University
G. Nowak
Instituto de Astrofísica de Canarias
Universidad de la Laguna
Martin Pätzold
Universität zu Köln
Enric Palle
Universidad de la Laguna
Instituto de Astrofísica de Canarias
Carina Persson
Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik
H. Rauer
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
Technische Universität Berlin
I. Ribas
Consejo Superior de Investigaciones Científicas (CSIC)
Alexis M. S. Smith
Deutsches Zentrums für Luft- und Raumfahrt (DLR)
V. Van Eylen
Universiteit Leiden
Astronomical Journal
0004-6256 (ISSN) 1538-3881 (eISSN)
Vol. 155 3 124Exoplaneter från rymden - CHEOPS och PLATO, ESA's nästa två missioner
Rymdstyrelsen (174/18), 2017-01-01 -- 2022-12-31.
Ämneskategorier (SSIF 2011)
Meteorologi och atmosfärforskning
Astronomi, astrofysik och kosmologi
Atom- och molekylfysik och optik
DOI
10.3847/1538-3881/aaaa6e