A 38 Million Year Old Neptune-sized Planet in the Kepler Field

L. G. Bouma; J. L. Curtis; K. Masuda; L. A. Hillenbrand; G. Stefansson; H. Isaacson; N. Narita; A. Fukui; M. Ikoma; M. Tamura; A. L. Kraus; E. Furlan; C. L. Gnilka; K. V. Lester; S. B. Howell

doi:10.3847/1538-3881/ac4966

The Astronomical Journal (Jan 2022)

A 38 Million Year Old Neptune-sized Planet in the Kepler Field

L. G. Bouma,
J. L. Curtis,
K. Masuda,
L. A. Hillenbrand,
G. Stefansson,
H. Isaacson,
N. Narita,
A. Fukui,
M. Ikoma,
M. Tamura,
A. L. Kraus,
E. Furlan,
C. L. Gnilka,
K. V. Lester,
S. B. Howell

Affiliations

L. G. Bouma: ORCiD; Cahill Center for Astrophysics, California Institute of Technology , Pasadena, CA 91125, USA ; [email protected]; Department of Astrophysical Sciences, Princeton University , 4 Ivy Lane, Princeton, NJ 08540, USA
J. L. Curtis: ORCiD; Department of Astronomy, Columbia University , 550 West 120th Street, New York, NY 10027, USA; Department of Astrophysics, American Museum of Natural History , New York, NY 10024, USA
K. Masuda: ORCiD; Department of Earth and Space Science, Osaka University , Osaka 560-0043, Japan
L. A. Hillenbrand: Cahill Center for Astrophysics, California Institute of Technology , Pasadena, CA 91125, USA ; [email protected]
G. Stefansson: ORCiD; Department of Astrophysical Sciences, Princeton University , 4 Ivy Lane, Princeton, NJ 08540, USA
H. Isaacson: ORCiD; Astronomy Department, University of California , Berkeley, CA 94720, USA
N. Narita: ORCiD; Komaba Institute for Science, The University of Tokyo , Tokyo 153-8902, Japan; Japan Science and Technology Agency , PRESTO, Tokyo 153-8902, Japan; Astrobiology Center , Tokyo 181-8588, Japan; Instituto de Astrofísica de Canarias (IAC) , E-38205 La Laguna, Tenerife, Spain
A. Fukui: ORCiD; Komaba Institute for Science, The University of Tokyo , Tokyo 153-8902, Japan; Instituto de Astrofísica de Canarias (IAC) , E-38205 La Laguna, Tenerife, Spain
M. Ikoma: ORCiD; Division of Science, National Astronomical Observatory of Japan , Tokyo 181-8588, Japan
M. Tamura: ORCiD; Astrobiology Center , Tokyo 181-8588, Japan; Division of Science, National Astronomical Observatory of Japan , Tokyo 181-8588, Japan; Department of Astronomy, The University of Tokyo , Tokyo 113-0033, Japan
A. L. Kraus: ORCiD; Department of Astronomy, The University of Texas at Austin , Austin, TX 78712, USA
E. Furlan: ORCiD; NASA Exoplanet Science Institute, Caltech/IPAC , Pasadena, CA 91125, USA
C. L. Gnilka: ORCiD; NASA Exoplanet Science Institute, Caltech/IPAC , Pasadena, CA 91125, USA; NASA Ames Research Center , Moffett Field, CA 94035, USA
K. V. Lester: ORCiD; NASA Ames Research Center , Moffett Field, CA 94035, USA
S. B. Howell: ORCiD; NASA Ames Research Center , Moffett Field, CA 94035, USA

DOI: https://doi.org/10.3847/1538-3881/ac4966
Journal volume & issue: Vol. 163, no. 3
p. 121

Abstract

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Kepler 1627A is a G8V star previously known to host a 3.8 R _⊕ planet on a 7.2 day orbit. The star was observed by the Kepler space telescope because it is nearby ( d = 329 pc) and it resembles the Sun. Here, we show using Gaia kinematics, TESS stellar rotation periods, and spectroscopic lithium abundances that Kepler 1627 is a member of the ${38}_{-5}^{+6}$ Myr old δ Lyr cluster. To our knowledge, this makes Kepler 1627Ab the youngest planet with a precise age yet found by the prime Kepler mission. The Kepler photometry shows two peculiarities: the average transit profile is asymmetric, and the individual transit times might be correlated with the local light-curve slope. We discuss possible explanations for each anomaly. More importantly, the δ Lyr cluster is one of ∼10 ^3 coeval groups whose properties have been clarified by Gaia. Many other exoplanet hosts are candidate members of these clusters; their ages can be verified with the trifecta of Gaia, TESS, and ground-based spectroscopy.

Published in The Astronomical Journal

ISSN: 0004-6256 (Print); 1538-3881 (Online)
Publisher: IOP Publishing
Country of publisher: United Kingdom
LCC subjects: Science: Astronomy
Website: https://iopscience.iop.org/journal/1538-3881

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