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WASP-20 IS A CLOSE VISUAL BINARY WITH A TRANSITING HOT JUPITER

Evans, Daniel F.; Southworth, John; Smalley, Barry

WASP-20 IS A CLOSE VISUAL BINARY WITH A TRANSITING HOT JUPITER Thumbnail


Authors

Daniel F. Evans



Abstract

We announce the discovery that WASP-20 is a binary stellar system, consisting of two components separated by 0.2578 ± 0farcs0007 on the sky, with a flux ratio of 0.4639 ± 0.0015 in the K-band. It has previously been assumed that the system consists of a single F9 V star, with photometric and radial velocity signals consistent with a low-density transiting giant planet. With a projected separation of approximately 60 au between the two components, the detected planetary signals almost certainly originate from the brighter of the two stars. We reanalyze previous observations allowing for two scenarios, "planet transits A" and "planet transits B," finding that both cases remain consistent with a transiting gas giant. However, we rule out the "planet transits B" scenario because the observed transit duration requires star B to be significantly evolved, and therefore have an age much greater than star A. We outline further observations that can be used to confirm this finding. Our preferred "planet transits A" scenario results in the measured mass and radius of the planet increasing by 4s and 1s, respectively.

Citation

Evans, D. F., Southworth, J., & Smalley, B. (2016). WASP-20 IS A CLOSE VISUAL BINARY WITH A TRANSITING HOT JUPITER. Astrophysical Journal Letters, 833, Article L19. https://doi.org/10.3847/2041-8213/833/2/L19

Journal Article Type Article
Acceptance Date Nov 25, 2016
Online Publication Date Dec 13, 2016
Publication Date Dec 13, 2016
Journal Astrophysical Journal Letters
Print ISSN 2041-8205
Publisher American Astronomical Society
Peer Reviewed Peer Reviewed
Volume 833
Article Number L19
DOI https://doi.org/10.3847/2041-8213/833/2/L19
Keywords binaries, visual, planets and satellites, detection, stars, individual (WASP-20), techniques, high angular resolution
Publisher URL http://dx.doi.org/10.3847/2041-8213/833/2/L19

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