Five Planets Transiting a Ninth Magnitude Star

Abstract

The Kepler mission has revealed a great diversity of planetary systems and architectures, but most of the planets discovered by Kepler orbit faint stars. Using new data from the K2 mission, we present the discovery of a five planet system transiting a bright (V = 8.9, K = 7.7) star called HIP 41378. HIP 41378 is a slightly metal-poor late F-type star with moderate rotation (v sin(i) = 7 km/s) and lies at a distance of 116 +/- 18 from Earth. We find that HIP 41378 hosts two sub-Neptune sized planets orbiting 3.5% outside a 2:1 period commensurability in 15.6 and 31.7 day orbits. In addition, we detect three planets which each transit once during the 75 days spanned by K2 observations. One planet is Neptune sized in a likely ~160 day orbit, one is sub-Saturn sized likely in a ~130 day orbit, and one is a Jupiter sized planet in a likely ~1 year orbit. We show that these estimates for the orbital periods can be made more precise by taking into account dynamical stability considerations. We also calculate the distribution of stellar reflex velocities expected for this system, and show that it provides a good target for future radial velocity observations. If a precise orbital period can be determined for the outer Jovian planet through future observations, it will be an excellent candidate for follow-up transit observations to study its atmosphere and measure its oblateness.

Accepted by ApJL. 12 pages, 6 figures, 2 tables

References in corpus (20)

• The Transiting Exoplanet Survey Satellite
• The K2 Mission: Characterization and Early results
• Most 1.6 Earth-Radius Planets are not Rocky
• A Technique for Extracting Highly Precise Photometry for the Two-Wheeled Kepler Mission
• Basic physical parameters of a selected sample of evolved stars
• A Precise Water Abundance Measurement for the Hot Jupiter WASP-43b
• Three regimes of extrasolar planets inferred from host star metallicities
• The Mass of KOI-94d and a Relation for Planet Radius, Mass, and Incident Flux
• Exoplanet population inference and the abundance of Earth analogs from noisy, incomplete catalogs
• The Mass of Kepler-93b and The Composition of Terrestrial Planets
• An ancient extrasolar system with five sub-Earth-size planets
• A nearby M star with three transiting super-Earths discovered by K2
• The period ratio distribution of Kepler's candidate multiplanet systems
• Characterizing the Orbital Eccentricities of Transiting Extrasolar Planets with Photometric Observations
• Characterizing K2 Planet Discoveries: A super-Earth transiting the bright K-dwarf HIP 116454
• High-efficiency Autonomous Laser Adaptive Optics
• Bayesian priors for the eccentricity of transiting planets
• Constraining the Oblateness of Kepler Planets
• Characterizing Long-Period Transiting Planets Observed by Kepler
• Discovery of a Transiting Planet Near the Snow-Line

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• The Random Transiter -- EPIC 249706694/HD 139139