K2-137 b: an Earth-sized planet in a 4.3-h orbit around an M-dwarf
Journal article, 2018

We report the discovery in K2's Campaign 10 of a transiting terrestrial planet in an ultra-short-period orbit around an M3-dwarf. K2-137 b completes an orbit in only 4.3 h, the second shortest orbital period of any known planet, just 4 min longer than that of KOI 1843.03, which also orbits an M-dwarf. Using a combination of archival images, adaptive optics imaging, radial velocity measurements, and light-curve modelling, we show that no plausible eclipsing binary scenario can explain the K2 light curve, and thus confirm the planetary nature of the system. The planet, whose radius we determine to be 0.89 ± 0.09 R⊕, and which must have an iron mass fraction greater than 0.45, orbits a star of mass 0.463 ± 0.052 M⊙ and radius 0.442 ± 0.044 R⊙.

planets and satellites: individual: K2-137 b

planets and satellites: detection


A. M. S. Smith

J. Cabrera

Sz. Csizmadia

F. Dai

D. Gandolfi

T. Hirano

J. N. Winn

S. Albrecht

R. Alonso

G. Antoniciello

O. Barragán

H. Deeg

Ph. Eigmüller

M. Endl

A. Erikson

Malcolm Fridlund

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics

A. Fukui

S. Grziwa

E. W. Guenther

A. Hatzes

D. Hidalgo

A. W. Howard

H. Isaacson

J. Korth

M. Kuzuhara

J. Livingston

N. Narita

D. Nespral

G. Nowak

E. Palle

M. Patzold

Carina Persson

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics

E. Petigura

J. Prieto-Arranz

H. Rauer

I. Ribas

V. Van Eylen

Monthly Notices of the Royal Astronomical Society

0035-8711 (ISSN) 1365-2966 (eISSN)

Vol. 474 4 5523-5533

Subject Categories

Astronomy, Astrophysics and Cosmology


Basic sciences



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