摘要：We report the discovery of a compact multi-planet system orbiting the relatively nearby (78pc) and bright (K=8.9) K-star, K2-266 (EPIC 248435473). We identify up to six possible planets orbiting K2-266 with estimated periods of P b =0.66, P .02 =6.1, P c =7.8, P d =14.7, P e =19.5, and P .06 =56.7 days, and radii of R P =3.3 R ⊕ , 0.646 R ⊕ , 0.705 R ⊕ , 2.93 R ⊕ , 2.73 R ⊕ , and 0.90 R ⊕ , respectively. We are able to confirm the planetary nature of two of these planets (d and e) by analyzing their transit timing variations ( = - + Å m M 8.9 d 3.8 5.7 and = - + Å m M 14.3 e 5.0 6.4), confidently validate the planetary nature of two other planets (b and c), and classify the last two as planetary candidates (K2-266.02 and .06). From a simultaneous fit of all six possible planets, we find that K2-266 b’s orbit has an inclination of 75°.32 while the other five planets have inclinations of 87°–90°. This observed mutual misalignment may indicate that K2-266 b formed differently from the other planets in the system. The brightness of the host star and the relatively large size of the sub-Neptune sized planets d and e make them well-suited for atmospheric characterization efforts with facilities like the Hubble Space Telescope and upcoming James Webb Space Telescope. We also identify an 8.5 day transiting planet candidate orbiting EPIC 248435395, a co-moving companion to K2-266.
关键词：planetary systems;planets and satellites: detection;stars: individual (K2-266, EPIC 248435395)
