K2-264: a transiting multiplanet system in the Praesepe open cluster
Journal article, 2019

Planet host stars with well-constrained ages provide a rare window to the time domain of planet formation and evolution. The NASA K2 mission has enabled the discovery of the vast majority of known planets transiting stars in clusters, providing a valuable sample of planets with known ages and radii. We present the discovery of two planets transiting K2-264, an M2 dwarf in the intermediate age (600-800 Myr) Praesepe open cluster (also known as the Beehive Cluster, M44, or NGC 2632), which was observed by K2 during Campaign 16. The planets have orbital periods of 5.8 and 19.7 d, and radii of 2.2 ± 0.2 and 2.7 ± 0.2R⊕, respectively, and their equilibrium temperatures are 496 ± 10 and 331 ± 7 K, making this a system of two warm sub-Neptunes. When placed in the context of known planets orbiting field stars of similar mass to K2-264, these planets do not appear to have significantly inflated radii, as has previously been noted for some cluster planets. As the second known system of multiple planets transiting a star in a cluster, K2-264 should be valuable for testing theories of photoevaporation in systems of multiple planets. Follow-up observations with current near-infrared (NIR) spectrographs could yield planet mass measurements, which would provide information about the mean densities and compositions of small planets soon after photoevaporation is expected to have finished. Follow-up NIR transit observations using Spitzer or large ground-based telescopes could yield improved radius estimates, further enhancing the characterization of these interesting planets.

techniques: photometric

techniques: high angular resolution

planets and satellites: detection


J. Livingston

F. Dai

T. Hirano

D. Gandolfi

A. A. Trani

G. Nowak

W. D. Cochran

M. Endl

S. Albrecht

O. Barragan

J. Cabrera

Sz. Csizmadia

J. P. de Leon

H. Deeg

Ph Eigmüller

A. Erikson

Malcolm Fridlund

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics, Galactic Astrophysics

A. Fukui

S. Grziwa

E. W. Guenther

A. P. Hatzes

J. Korth

M. Kuzuhara

P. Montañes

N. Narita

D. Nespral

E. Palle

M. Pätzold

Carina Persson

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics, Galactic Astrophysics

J. Prieto-Arranz

H. Rauer

M. Tamura

V. Van Eylen

J. N. Winn

Monthly Notices of the Royal Astronomical Society

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

Vol. 484 1 8-18

Exoplanets from space – CHEOPS and PLATO, ESA’s next two projects

Swedish National Space Board, 2017-01-01 -- 2022-12-31.

Subject Categories

Astronomy, Astrophysics and Cosmology


Basic sciences



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