Three Small Planets Transiting the Bright Young Field Star K2-233

May 2018 • 2018AJ....155..222D

Authors • David, Trevor J. • Crossfield, Ian J. M. • 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

Abstract • 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}_\oplus , R _c = 1.34 ± 0.08 {R}_\oplus ), while the outer planet is a warm sub-Neptune (R _d = 2.6 ± 0.1 {R}_\oplus ). We estimate the stellar age to be {360}_-140⁺⁴⁹⁰ 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.

Links

• SIMBAD http://simbad.u-strasbg.fr/simbo.pl?bibcode=2018AJ....155..222D
• PDF https://iopscience.iop.org/article/10.3847/1538-3881/aabde8/pdf
• PDF https://stacks.iop.org/1538-3881/155/222/pdf
• PREPRINT http://arxiv.org/abs/1803.05056
• DATA http://exoplanetarchive.ipac.caltech.edu/cgi-bin/DisplayOverview/nph-DisplayOverview?type=REFERENCE&bibcode=2018AJ....155..222D
• DATA https://archive.stsci.edu/mastbibref.php?bibcode=2018AJ....155..222D
• DATA https://irsa.ipac.caltech.edu/bibdata/2018/D/2018AJ....155..222D.html
• ELECTR https://doi.org/10.3847%2F1538-3881%2Faabde8