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: radial velocities

techniques: photometric

techniques: spectroscopic

stars: individual (K2-155 = EPIC 210897587)

planets and satellites: detection

Författare

T. Hirano

Organisation okänd

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 Middletown

N. Joshua

Princeton University

E. W. Guenther

Thüringer Landessternwarte Tautenburg

J. Prieto-Arranz

Instituto Astrofisico de Canarias

Universidad de la Laguna

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 Astrofisico de Canarias

P. Eigmüller

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

Anders Erikson

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

Malcolm Fridlund

Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik

Universiteit Leiden

A. Fukui

National Institutes of Natural Sciences - National Astronomical Observatory of Japan

S. Grziwa

Universität zu Köln

A. Hatzes

Thüringer Landessternwarte Tautenburg

Judith Korth

Universität zu Köln

Norio Narita

University of Tokyo

National Institutes of Natural Sciences

National Institutes of Natural Sciences - National Astronomical Observatory of Japan

David Nespral

Universidad de la Laguna

Instituto Astrofisico de Canarias

Prajwal Niraula

Wesleyan University Middletown

G. Nowak

Universidad de la Laguna

Instituto Astrofisico de Canarias

Martin Pätzold

Universität zu Köln

Enric Palle

Universidad de la Laguna

Instituto Astrofisico de Canarias

Carina Persson

Chalmers, Rymd-, geo- och miljövetenskap, Astronomi och plasmafysik, Galaktisk astrofysik

H. Rauer

Technische Universität Berlin

Deutsches Zentrums für Luft- und Raumfahrt (DLR)

I. Ribas

CSIC - Instituto de Ciencias del Espacio (ICE)

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 3 124

Exoplaneter från rymden - CHEOPS och PLATO

Rymdstyrelsen, 2017-01-01 -- 2022-12-31.

Ämneskategorier

Meteorologi och atmosfärforskning

Astronomi, astrofysik och kosmologi

Atom- och molekylfysik och optik

DOI

10.3847/1538-3881/aaaa6e

Mer information

Senast uppdaterat

2018-10-12