The K2-138 system : a near-resonant chain of five sub-neptune planets discovered by citizen scientists

Christiansen, Jessie L. and Crossfield, Ian J. M. and Barentsen, Geert and Lintott, Chris J. and Barclay, Thomas and Simmons, Brooke . D. and Petigura, Erik and Schlieder, Joshua E. and Dressing, Courtney D. and Vanderburg, Andrew and Allen, Campbell and Mcmaster, Adam and Miller, Grant and Veldthuis, Martin and Allen, Sarah and Wolfenbarger, Zach and Cox, Brian and Zemiro, Julia and Howard, Andrew W. and Livingston, John and Sinukoff, Evan and Catron, Timothy and Grey, Andrew and Kusch, Joshua J. E. and Terentev, Ivan and Vales, Martin and Kristiansen, Martti H. (2018) The K2-138 system : a near-resonant chain of five sub-neptune planets discovered by citizen scientists. The Astronomical Journal, 155 (2): 57. ISSN 0004-6256

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K2-138 is a moderately bright (V = 12.2, K = 10.3) main-sequence K star observed in Campaign 12 of the NASA K2 mission. It hosts five small (1.6–3.3 ${R}_{\oplus }$) transiting planets in a compact architecture. The periods of the five planets are 2.35, 3.56, 5.40, 8.26, and 12.76 days, forming an unbroken chain of near 3:2 resonances. Although we do not detect the predicted 2–5 minute transit timing variations (TTVs) with the K2 timing precision, they may be observable by higher-cadence observations with, for example, Spitzer or CHEOPS. The planets are amenable to mass measurement by precision radial velocity measurements, and therefore K2-138 could represent a new benchmark system for comparing radial velocity and TTV masses. K2-138 is the first exoplanet discovery by citizen scientists participating in the Exoplanet Explorers project on the Zooniverse platform.

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Journal Article
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The Astronomical Journal
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This is an author-created, un-copyedited version of an article accepted for publication/published in The Astronomical Journal. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it
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?? astronomy and astrophysicsspace and planetary science ??
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21 Sep 2018 11:40
Last Modified:
15 Jul 2024 18:20