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One of the closest exoplanet pairs to the 3:2 mean motion resonance: K2-19b and c

D. J. Armstrong, A. Santerne, D. Veras, S. C. C. Barros, O. Demangeon, J. Lillo Box, J. McCormac, H. P. Osborn, M. Tsantaki, J.-M. Almenara, D. Barrado-Navascues, I. Boisse, A. S. Bonomo, D. J. A. Brown, G. Bruno, J. Rey Cerda, B. Courcol, M. Deleuil, R. F. Díaz, A. P. Doyle, G. Hébrard, J. Kirk, K. W. F. Lam, D. Pollacco, A. S. Rajpurohit, J. Spake, S. R. Walker


Aims. The K2 mission has recently begun to discover new and diverse planetary systems. In December 2014, Campaign 1 data from the mission was released, providing high-precision photometry for ~22 000 objects over an 80-day timespan. We searched these data with the aim of detecting more important new objects.
Methods. Our search through two separate pipelines led to the independent discovery of K2-19b and c, a two-planet system of Neptune-sized objects (4.2 and 7.2 R), orbiting a K dwarf extremely close to the 3:2 mean motion resonance. The two planets each show transits, sometimes simultaneously owing to their proximity to resonance and the alignment of conjunctions.
Results. We obtained further ground-based photometry of the larger planet with the NITES telescope, demonstrating the presence of large transit timing variations (TTVs), and used the observed TTVs to place mass constraints on the transiting objects under the hypothesis that the objects are near but not in resonance. We then statistically validated the planets through the PASTIS tool, independently of the TTV analysis.

planets and satellites: individual: EPIC201505350c, planets and satellites: detection, planets and satellites: general, planets and satellites: dynamical evolution and stability, planets and satellites: individual: EPIC201505350b

Astronomy & Astrophysics
Volume 582, Number of pages A33
2015 October

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Faculdade de Ciências da Universidade de Lisboa Universidade do Porto Faculdade de Ciências e Tecnologia da Universidade de Coimbra
Fundação para a Ciência e a Tecnologia COMPETE 2020 PORTUGAL 2020 União Europeia