Three Small Planets Transiting a Hyades Star

TL;DR

This paper reports the discovery of three small, young transiting planets around a Hyades star, providing valuable data for understanding planet formation and evolution in stellar clusters.

Contribution

First detection of multiple transiting planets in a Hyades cluster star, offering insights into early planetary system development.

Findings

Planets are among the smallest and youngest known transiting planets.

The host star's brightness makes the planets ideal for future detailed studies.

The system serves as a benchmark for testing planet formation theories.

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.