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
Kepler 1627A is a G8V star previously known to host a 3.8 Earth-radius 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 ± 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 about 103 coeval groups whose properties have been clarified by Gaia. Many other exoplanet hosts are candidate members of these clusters; these memberships can be verified with the trifecta of Gaia, TESS, and ground-based spectroscopy.
Comments: AJ accepted, Table 3 available upon request
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2112.14776 [astro-ph.EP] (or arXiv:2112.14776v1 [astro-ph.EP] for this version)
Submission history
From: Luke Bouma
[v1] Wed, 29 Dec 2021 19:00:00 UTC (6,151 KB)
