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

Abstract

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.

Three Super-Earths Transiting the Nearby Star GJ 9827

“…Sinukoff et al (2016) reported the detection of 11 multiplanetary systems from K2 Campaigns 1 and 2. However, there are few such systems around nearby stars (Armstrong et al 2015;Crossfield et al 2015;Gandolfi et al 2017), and only a handful around brighter stars that are suitable for spectroscopic characterization.…”

THEK2-ESPRINT PROJECT III: A CLOSE-IN SUPER-EARTH AROUND A METAL-RICH MID-M DWARF

“…K2 has so far unveiled many planetary systems with distinguishing characteristics, including a compact multi-planet system with sub-Saturn-mass planets in 3:2 mean motion resonance (Armstrong et al 2015), multiple systems with Earth-to super-Earth-sized planets around rather bright M dwarfs Petigura et al 2015), and a disintegrating minor planet around a white dwarf . In order to fully exploit the worldwide ground facilities for K2 follow-ups, we started the ESPRINT (Equipo de Seguimiento de Planetas Rocosos Intepretando sus Transitos) collaboration, which aims to discover and characterize unique transiting planets unveiled by K2.…”

The Way Forward

“…The first results from K2 have now been published and it seems like the predictions before implementing the mission have been met or even superseded (Barros et al 2015;Narita et al 2015;Armstrong et al 2015;Becker et al 2015).…”