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), 30 false positives, and 63 remaining candidates. Our validated systems span a range of properties, with median values of R-P = 2.3 R-circle plus, P = 8.6 days, T-eff = 5300 K, and Kp = 12.7 mag. 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-circle plus, Kp = 9-13. mag). Of particular interest are 76 planets smaller than 2 R-circle plus, 15 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 (<2 R-circle plus) and larger for candidates with radii >8 R-circle plus and/or with P < 3 days. Extrapolation of the current planetary yield suggests that K2 will discover between 500 and 1000 planets in its planned four-year mission, assuming sufficient follow-up resources are available. Efficient observing and analysis, together with an organized and coherent follow-up strategy, are essential for maximizing the efficacy of planet-validation efforts for K2, TESS, and future large-scale surveys.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/624074 |
| Date | 02 September 2016 |
| Creators | 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., Lepine, Sebastien, 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, Bjorn, Scott, Nic, Deacon, Niall, Aller, Kimberly M., Hansen, Brad M. S., Mancini, Luigi, Ciceri, Simona, Brahm, Rafael, Jordan, Andres, Knutson, Heather A., Henning, Thomas, Bonnefoy, Michael, Liu, Michael C., Crepp, Justin R., Lothringer, Joshua, Hinz, Phil, Bailey, Vanessa, Skemer, Andrew, Defrere, Denis |
| Contributors | Univ Arizona, Lunar & Planetary Lab |
| Publisher | IOP PUBLISHING LTD |
| Source Sets | University of Arizona |
| Language | English |
| Detected Language | English |
| Type | Article |
| Rights | © 2016. The American Astronomical Society. All rights reserved. |
| Relation | http://stacks.iop.org/0067-0049/226/i=1/a=7?key=crossref.fa1a9b34870d49d81d988791bc851432 |
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