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
planets and satellites: detection
techniques: high angular resolution
Author
J. Livingston
JSPS
University of Tokyo
F. Dai
Massachusetts Institute of Technology (MIT)
Princeton University
T. Hirano
Tokyo Institute of Technology
D. Gandolfi
University of Turin
A. A. Trani
University of Tokyo
JSPS
G. Nowak
Instituto de Astrofísica de Canarias
University of La Laguna
W. D. Cochran
University of Texas
M. Endl
University of Texas
S. Albrecht
Aarhus University
O. Barragan
University of Turin
J. Cabrera
German Aerospace Center (DLR)
Sz. Csizmadia
German Aerospace Center (DLR)
J. P. de Leon
University of Tokyo
H. Deeg
Instituto de Astrofísica de Canarias
University of La Laguna
Ph Eigmüller
German Aerospace Center (DLR)
Technische Universität Berlin
A. Erikson
German Aerospace Center (DLR)
Malcolm Fridlund
Leiden University
Chalmers, Space, Earth and Environment, Onsala Space Observatory
A. Fukui
Instituto de Astrofísica de Canarias
National Astronomical Observatory of Japan
S. Grziwa
University of Cologne
E. W. Guenther
Thüringer Landessternwarte Tautenburg
A. P. Hatzes
Thüringer Landessternwarte Tautenburg
Judith Korth
University of Cologne
M. Kuzuhara
National Astronomical Observatory of Japan
National Institutes of Natural Sciences
P. Montañes
Instituto de Astrofísica de Canarias
University of La Laguna
N. Narita
National Astronomical Observatory of Japan
National Institutes of Natural Sciences
Instituto de Astrofísica de Canarias
University of Tokyo
D. Nespral
University of La Laguna
Instituto de Astrofísica de Canarias
E. Palle
Instituto de Astrofísica de Canarias
University of La Laguna
M. Pätzold
University of Cologne
Carina Persson
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
J. Prieto-Arranz
Instituto de Astrofísica de Canarias
University of La Laguna
H. Rauer
German Aerospace Center (DLR)
Freie Universität Berlin
Technische Universität Berlin
M. Tamura
University of Tokyo
National Institutes of Natural Sciences
National Astronomical Observatory of Japan
V. Van Eylen
Leiden University
J. N. Winn
Princeton University
Monthly Notices of the Royal Astronomical Society
0035-8711 (ISSN) 1365-2966 (eISSN)
Vol. 484 1 8-18Exoplanets from space – CHEOPS and PLATO, ESA’s next two projects
Swedish National Space Board (174/18), 2017-01-01 -- 2022-12-31.
Subject Categories (SSIF 2011)
Astronomy, Astrophysics and Cosmology
Roots
Basic sciences
Infrastructure
Onsala Space Observatory
DOI
10.1093/mnras/sty3464