Characterizing K2 Planet Discoveries: A super-Earth transiting the bright K-dwarf HIP 116454

Abstract

We report the first planet discovery from the two-wheeled Kepler (K2) mission: HIP 116454 b. The host star HIP 116454 is a bright (V = 10.1, K = 8.0) K1-dwarf with high proper motion, and a parallax-based distance of 55.2 +/- 5.4 pc. Based on high-resolution optical spectroscopy, we find that the host star is metal-poor with [Fe/H] = -.16 +/- .18, and has a radius R = 0.716 +/- .0024 R_sun and mass M = .775 +/- .027 Msun. The star was observed by the Kepler spacecraft during its Two-Wheeled Concept Engineering Test in February 2014. During the 9 days of observations, K2 observed a single transit event. Using a new K2 photometric analysis technique we are able to correct small telescope drifts and recover the observed transit at high confidence, corresponding to a planetary radius of Rp = 2.53 +/- 0.18 Rearth. Radial velocity observations with the HARPS-N spectrograph reveal a 11.82 +/- 1.33 Mearth planet in a 9.1 day orbit, consistent with the transit depth, duration, and ephemeris. Follow-up photometric measurements from the MOST satellite confirm the transit observed in the K2 photometry and provide a refined ephemeris, making HIP 116454 b amenable for future follow-up observations of this latest addition to the growing population of transiting super-Earths around nearby, bright stars.

16 pages, 8 figures. Accepted by ApJ

References in corpus (12)

• The K2 Mission: Characterization and Early results
• Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics
• EXOFAST: A fast exoplanetary fitting suite in IDL
• A Technique for Extracting Highly Precise Photometry for the Two-Wheeled Kepler Mission
• Basic physical parameters of a selected sample of evolved stars
• Radial velocity planets de-aliased. A new, short period for Super-Earth 55 Cnc e
• The Exoplanet Orbit Database II: Updates to exoplanets.org
• Hubble Space Telescope Near-IR Transmission Spectroscopy of the Super-Earth HD 97658b
• The Kepler-10 planetary system revisited by HARPS-N: A hot rocky world and a solid Neptune-mass planet
• High-efficiency Autonomous Laser Adaptive Optics
• Kepler-93b: A Terrestrial World Measured to within 120 km, and a Test Case for a New Spitzer Observing Mode
• Statistical Eclipses of Close-in Kepler Sub-Saturns

Cited by in corpus (30)

• Inferring probabilistic stellar rotation periods using Gaussian processes
• 197 Candidates and 104 Validated Planets in K2's First Five Fields
• Cold Jupiters and improved masses in 38 Kepler and K2 small planet systems from 3661 HARPS-N radial velocities. No excess of cold Jupiters in small planet systems
• Discovery of a Third Transiting Planet in the Kepler-47 Circumbinary System
• K2 Variable Catalogue: Variable Stars and Eclipsing Binaries in K2 Campaigns 1 and 0
• The K2 Galactic Archaeology Program Data Release 1: Asteroseismic results from Campaign 1
• Five Planets Transiting a Ninth Magnitude Star
• The Densities of Planets in Multiple Stellar Systems
• Precise Masses in the WASP-47 System
• A pair of Sub-Neptunes transiting the bright K-dwarf TOI-1064 characterised with CHEOPS
• An Overabundance of Low-density Neptune-like Planets
• No Conclusive Evidence for Transits of Proxima b in MOST photometry
• Looking at Blazar Light Curve Periodicities with Gaussian Processes
• K2-66b and K2-106b: Two extremely hot sub-Neptune-size planets with high densities
• Shallower radius valley around low-mass hosts: Evidence for icy planets, collisions or high-energy radiation scatter
• Near Mean-motion Resonances in the Systems Observed by Kepler: Affected by Mass Accretion and Type I Migration
• Revisiting WASP-47 with ESPRESSO and TESS
• Ground-based photometry of the 21-day Neptune HD106315c
• Robust detection of quasi-periodic variability: A HAWKI mini survey of late T dwarfs
• On the radial velocity detection of additional planets in transiting, slowly rotating M-dwarf systems: the case of GJ 1132
• EXPRES. II. Searching for Planets Around Active Stars: A Case Study of HD 101501
• K2-280b -- a low density warm sub-Saturn around a mildly evolved star
• Implications of an improved water equation of state for water-rich planets
• Statistics of Magrathea exoplanets beyond the Main Sequence. Simulating the long-term evolution of circumbinary giant planets with TRES
• Kepler's Last Planet Discoveries: Two New Planets and One Single-Transit Candidate from K2 Campaign 19
• Spectroscopy of TOI-1259B -- an unpolluted white dwarf companion to an inflated warm Saturn
• The Occurrence-weighted Median Planets Discovered by Transit Surveys Orbiting Solar-type Stars and Their Implications for Planet Formation and Evolution
• A Cool Earth-sized Planet Candidate Transiting a Tenth Magnitude K-dwarf From K2
• Tidal star-planet interaction and its observed impact on stellar activity in planet-hosting wide binary systems
• Dynamical architecture of the HD 107148 system