Transiting planet candidate from K2 with the longest period
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Context. We present the transit and follow-up of a single transit event from Campaign 14 of K2, EPIC248847494b, which has a duration of 54 h and a 0.18% depth. Aims. Using photometric tools and conducting radial velocity follow-up, we vet and characterise this very strong candidate. Methods. Owing to the long, unknown period, standard follow-up methods needed to be adapted. The transit was fitted using Namaste, and the radial velocity slope was measured and compared to a grid of planet-like orbits with varying masses and periods. These used stellar parameters measured from spectra and the distance as measured by Gaia. Results. Orbiting around a sub-giant star with a radius of 2.70 ± 0.12 RSol, the planet has a radius of 1.11−0.07+0.07 RJup and a period of 3650−1130+1280 days. The radial velocity measurements constrain the mass to be lower than 13 MJup, which implies a planet-like object. Conclusions. We have found a planet at 4.5 AU from a single-transit event. After a full radial velocity follow-up campaign, if confirmed, it will be the longest-period transiting planet discovered.
Giles , H A C , Osborn , H P , Blanco-Cuaresma , S , Lovis , C , Bayliss , D , Eggenberger , P , Cameron , A C , Kristiansen , M H , Turner , O , Bouchy , F & Udry , S 2018 , ' Transiting planet candidate from K2 with the longest period ' Astronomy & Astrophysics , vol. 615 , L13 . DOI: 10.1051/0004-6361/201833569
Astronomy & Astrophysics
© 2018, ESO. This work has been made available online in accordance with the publisher’s policies. This is the final published version of the work, which was originally published at https://doi.org/10.1051/0004-6361/201833569.
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