197 CANDIDATES and 104 VALIDATED PLANETS in K2's FIRST FIVE FIELDS
Author
Crossfield, Ian J M
Ciardi, David R.
Petigura, Erik A.
Sinukoff, Evan
Schlieder, Joshua E.
Howard, Andrew W.
Beichman, Charles A.
Isaacson, Howard
Dressing, Courtney D.
Christiansen, Jessie L.
Fulton, Benjamin J.
Lépine, Sébastien
Weiss, Lauren
Hirsch, Lea
Livingston, John
Baranec, Christoph
Law, Nicholas M.
Riddle, Reed
Ziegler, Carl
Howell, Steve B.
Horch, Elliott
Everett, Mark
Teske, Johanna
Martinez, Arturo O.
Obermeier, Christian
Benneke, Björn
Scott, Nic
Deacon, Niall
Aller, Kimberly M.
Hansen, Brad M S
Mancini, Luigi
Ciceri, Simona
Brahm, Rafael
Jordán, Andrés
Knutson, Heather A.
Henning, Thomas
Bonnefoy, Michaël
Liu, Michael C.
Crepp, Justin R.
Lothringer, Joshua
Hinz, Phil
Bailey, Vanessa
Skemer, Andrew
Defrere, Denis
Attention
2299/19178
Abstract
We present 197 planet candidates discovered using data from the first year of the NASA K2 mission (Campaigns 0-4), along with the results of an intensive program of photometric analyses, stellar spectroscopy, high-resolution imaging, and statistical validation. We distill these candidates into sets of 104 validated planets (57 in multi-planet systems), false positives, and 63 remaining candidates. Our validated systems span a range of properties, with median values of RP= 2.3 R⊕, P = 8.6 days, Teff = 5300 K, and Kp = 12.7mag. Stellar spectroscopy provides precise stellar and planetary parameters for most of these systems. We show that K2 has increased by 30% the number of small planets known to orbit moderately bright stars (1-4 R R⊕, Kp = 9-13 mag). Of particular interest are planets smaller than 2 R⊕, orbiting stars brighter than Kp = 11.5 mag, 5 receiving Earth-like irradiation levels, and several multi-planet systems - including 4 planets orbiting the M dwarf K2-72 near mean-motion resonances. By quantifying the likelihood that each candidate is a planet we demonstrate that our candidate sample has an overall false positive rate of 15%-30%, with rates substantially lower for small candidates (8 R⊕ and/or with P