- David, Trevor J;
- Crossfield, Ian JM;
- Benneke, Björn;
- Petigura, Erik A;
- Gonzales, Erica J;
- Schlieder, Joshua E;
- Yu, Liang;
- Isaacson, Howard T;
- Howard, Andrew W;
- Ciardi, David R;
- Mamajek, Eric E;
- Hillenbrand, Lynne A;
- Cody, Ann Marie;
- Riedel, Adric;
- Schwengeler, Hans Martin;
- Tanner, Christopher;
- Ende, Martin
We report the detection of three small transiting planets around the young K3 dwarf K2-233 (2MASS J15215519-2013539) from observations during Campaign 15 of the K2 mission. The star is relatively nearby (d = 69 pc) and bright (V = 10.7 mag, K s = 8.4 mag), making the planetary system an attractive target for radial velocity follow-up and atmospheric characterization with the James Webb Space Telescope. The inner two planets are hot super-Earths (R b = 1.40 ± 0.06 , R c = 1.34 ± 0.08 ), while the outer planet is a warm sub-Neptune (R d = 2.6 ± 0.1 ). We estimate the stellar age to be Myr based on rotation, activity, and kinematic indicators. The K2-233 system is particularly interesting given recent evidence for inflated radii in planets around similarly aged stars, a trend potentially related to photo-evaporation, core cooling, or both mechanisms.