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arXiv · 1710.07203

Three Small Planets Transiting a Hyades Star

John H. Livingston·Fei Dai·Teruyuki Hirano·Davide Gandolfi·Grzegorz Nowak·Michael Endl·Sergio Velasco·Akihiko Fukui·Norio Narita·Jorge Prieto-Arranz·Oscar Barragan·Felice Cusano·Simon Albrecht·Juan Cabrera·William D. Cochran·Szilard Csizmadia·Hans J. Deeg·Philipp Eigmüller·Anders Erikson·Malcolm Fridlund·Sascha Grziwa·Eike W. Guenther·Artie P. Hatzes·Kiyoe Kawauchi·Judith Korth·David Nespral·Enric Palle·Martin Pätzold·Carina M. Persson·Heike Rauer·Alexis M. S. Smith·Motohide Tamura·Yusuke Tanaka·Vincent Van Eylen·Noriharu Watanabe·Joshua N. Winn
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Abstract

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 $7.9757 \pm 0.0011$, $17.30681^{+0.00034}_{-0.00036}$, and $25.5715^{+0.0038}_{-0.0040}$ days, and radii of $1.05 \pm 0.16$, $3.14 \pm 0.36$, and $1.55^{+0.24}_{-0.21}$ $R_\oplus$, 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.

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John H. Livingston, Fei Dai, Teruyuki Hirano, Davide Gandolfi, Grzegorz Nowak, Michael Endl, Sergio Velasco, Akihiko Fukui, Norio Narita, Jorge Prieto-Arranz, Oscar Barragan, Felice Cusano, Simon Albrecht, Juan Cabrera, William D. Cochran, Szilard Csizmadia, Hans J. Deeg, Philipp Eigmüller, Anders Erikson, Malcolm Fridlund, Sascha Grziwa, Eike W. Guenther, Artie P. Hatzes, Kiyoe Kawauchi, Judith Korth, David Nespral, Enric Palle, Martin Pätzold, Carina M. Persson, Heike Rauer, Alexis M. S. Smith, Motohide Tamura, Yusuke Tanaka, Vincent Van Eylen, Noriharu Watanabe, Joshua N. Winn. 2017-10-19. Three Small Planets Transiting a Hyades Star. https://doi.org/10.3847/1538-3881%2Faaa841

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