We present the discovery of three small planets transiting K2-136 (LP 358 348, EPIC 247589423), a late K dwarf in the Hyades. The planets have orbital periods of 7.9757±0.0011, 17.30681−0.00036+0.00034, and 25.5715−0.0040+0.0038 days, and radii of 1.05±0.16, 3.14±0.36, and 1.55−0.21+0.24R⊕, respectively. With an age of 600-800 Myr, these planets are some of the smallest and youngest transiting planets known. Due to the relatively bright (J=9.1) host star, the planets are compelling targets for future characterization via radial velocity mass measurements and transmission spectroscopy. As the first known star with multiple transiting planets in a cluster, the system should be helpful for testing theories of planet formation and migration.
@article{arxiv.1710.07203,
title = {Three Small Planets Transiting a Hyades Star},
author = {John H. Livingston and Fei Dai and Teruyuki Hirano and Davide Gandolfi and Grzegorz Nowak and Michael Endl and Sergio Velasco and Akihiko Fukui and Norio Narita and Jorge Prieto-Arranz and Oscar Barragan and Felice Cusano and Simon Albrecht and Juan Cabrera and William D. Cochran and Szilard Csizmadia and Hans J. Deeg and Philipp Eigmüller and Anders Erikson and Malcolm Fridlund and Sascha Grziwa and Eike W. Guenther and Artie P. Hatzes and Kiyoe Kawauchi and Judith Korth and David Nespral and Enric Palle and Martin Pätzold and Carina M. Persson and Heike Rauer and Alexis M. S. Smith and Motohide Tamura and Yusuke Tanaka and Vincent Van Eylen and Noriharu Watanabe and Joshua N. Winn},
journal= {arXiv preprint arXiv:1710.07203},
year = {2018}
}