Presentation #303.06 in the session “Exoplanets and Systems: Discoveries”.
We report on a survey to find ultra-short-period planets or USPs (with periods < 1 day) using light curves from the K2 Mission’s Campaigns 0-8 and 10. We report 74 candidate USPs, of which 39 had not been previously announced. We also systematically searched for companion planets, and found that 22 of these USP systems have more than one transiting planet, including 15 with 2 planets (9 new systems), 6 with 3 planets (2 new systems), and 1 with 4 planets (0 new). Of the USPs, 27 have either been validated or confirmed, 11 for the first time in this work, while 14 of the longer-period companions can be independently validated, 2 for the first time. An additional 11 planets in multiple planet systems (4 USPs, 7 companions) can be validated after incorporating the reduced false positive probability that applies to multi-candidate planetary systems (Lissauer et al. 2012). We find that a high percentage of USPs (28%) are in systems with at least one additional transiting companion. This has implications for the kinds of planetary origins theories supported, and we will discuss the trends in system architecture with an eye toward revealing formation history.