ELEVEN MULTIPLANET SYSTEMS FROM K2 CAMPAIGNS 1 AND 2 AND THE MASSES OF TWO HOT SUPER-EARTHS
Howard, Andrew W.
Schlieder, Joshua E.
Crossfield, Ian J. M.
Ciardi, David R.
Fulton, B. J.
Isaacson, Howard T.
Aller, Kimberly M.
Beichman, Charles A.
Hansen, Brad M. S.
Knutson, Heather A.
Law, Nicholas M.
Liu, Michael C.
AffiliationUniv Arizona, Lunar & Planetary Lab
techniques: radial velocities
MetadataShow full item record
PublisherIOP PUBLISHING LTD
CitationELEVEN MULTIPLANET SYSTEMS FROM K2 CAMPAIGNS 1 AND 2 AND THE MASSES OF TWO HOT SUPER-EARTHS 2016, 827 (1):78 The Astrophysical Journal
JournalThe Astrophysical Journal
Rights© 2016. The American Astronomical Society. All rights reserved.
Collection InformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at email@example.com.
AbstractWe present a catalog of 11 multiplanet systems from Campaigns 1 and 2 of the K2 mission. We report the sizes and orbits of 26 planets split between seven two-planet systems and four three-planet systems. These planets stem from a systematic search of the K2 photometry for all dwarf stars observed by K2 in these fields. We precisely characterized the host stars with adaptive optics imaging and analysis of high-resolution optical spectra from Keck/HIRES and medium-resolution spectra from IRTF/SpeX. We confirm two planet candidates by mass detection and validate the remaining 24 candidates to >99% confidence. Thirteen planets were previously validated or confirmed by other studies, and 24 were previously identified as planet candidates. The planets are mostly smaller than Neptune (21/26 planets), as in the Kepler mission, and all have short periods (P < 50 days) due to the duration of the K2 photometry. The host stars are relatively bright (most have Kp < 12.5 mag) and are amenable to follow-up characterization. For K2-38, we measured precise radial velocities using Keck/HIRES and provide initial estimates of the planet masses. K2-38b is a short-period super-Earth with a radius of 1.55 +/- 0.16 R-circle plus, a mass of 12.0 +/- 2.9M(circle plus), and a high density consistent with an iron-rich composition. The outer planet K2-38c is a lower-density sub-Neptune-size planet with a radius of 2.42 +/- 0.29 R-circle plus and a mass of 9.9 +/- 4.6M(circle plus) that likely has a substantial envelope. This new planet sample demonstrates the capability of K2 to discover numerous planetary systems around bright stars.
VersionFinal published version
SponsorsNatural Sciences and Engineering Research Council of Canada (NSERC); Hubble Fellowship - Space Telescope Science Institute [HST-HF2-51365.001-A]; NASA [NAS 5-26555]; NASA Astrophysics Data Analysis Program grant; K2 Guest Observer Program; European Union Seventh Framework Programme (FP7) ; NASA Postdoctoral Program at NASA Ames Research Center; National Science Foundation Graduate Research Fellowship ; Office of Science of the U.S. Department of Energy [DE-AC02-05CH11231]; MAST [NNX09AF08G]; Robert Martin Ayers Sciences Fund; National Science Foundation [AST-0906060, AST-0960343, AST-1207891]; Mt. Cuba Astronomical Foundation; Robo-AO; University of Hawai'i; Alfred P. Sloan Foundation