K2-HERMES II. Planet-candidate properties from K2 Campaigns 1-13

Abstract

Accurate and precise radius estimates of transiting exoplanets are critical for understanding their compositions and formation mechanisms. To know the planet, we must know the host star in as much detail as possible. We present complete results for planet-candidate hosts from the K2-HERMES survey, which uses the HERMES multi-object spectrograph on the Anglo-Australian Telescope to obtain R$\sim$28,000 spectra for more than 30,000 K2 stars. We present complete host-star parameters and planet-candidate radii for 224 K2 candidate planets from C1-C13. Our results cast severe doubt on 30 K2 candidates, as we derive unphysically large radii, larger than 2 $R_{Jup}$. This work highlights the importance of obtaining accurate, precise, and self-consistent stellar parameters for ongoing large planet search programs - something that will only become more important in the coming years, as TESS begins to deliver its own harvest of exoplanets.

Accepted for publication in MNRAS. Full versions of online-only Tables 2 and 3 available on request. Same for Table 4, in exchange for the trick to make MNRAS style break long tables across pages

References in corpus (25)

• Direct Imaging of Multiple Planets Orbiting the Star HR 8799
• The K2 Mission: Characterization and Early results
• Optical Images of an Exosolar Planet 25 Light Years from Earth
• The GALAH Survey: Scientific Motivation
• Habitable Zones Around Main-Sequence Stars: Dependence on Planetary Mass
• Gaia Data Release 3 Properties and validation of the radial velocities
• Planetary Candidates Observed by Kepler VI: Planet Sample from Q1-Q16 (47 Months)
• EVEREST: Pixel Level Decorrelation of K2 Light curves
• The GALAH Survey: Observational Overview and Gaia DR1 companion
• 197 Candidates and 104 Validated Planets in K2's First Five Fields
• A Catalog of Kepler Habitable Zone Exoplanet Candidates
• Zodiacal Exoplanets in Time (ZEIT) IV: seven transiting planets in the Praesepe cluster
• The TESS-HERMES survey Data Release 1: high-resolution spectroscopy of the TESS southern continuous viewing zone
• On the Frequency of Potential Venus Analogs from Kepler Data
• The CORALIE survey for southern extra-solar planets XV. Discovery of two eccentric planets orbiting HD4113 and HD156846
• Four Sub-Saturns with Dissimilar Densities: Windows into Planetary Cores and Envelopes
• The K2 Galactic Archaeology Program Data Release 1: Asteroseismic results from Campaign 1
• The GALAH survey: The data reduction pipeline
• The GALAH survey: Chemical Tagging of Star Clusters and New Members in the Pleiades
• Five New Exoplanets Orbiting Three Metal-Rich, Massive Stars: Two-Planet Systems Including Long-Period Planets, and an Eccentric Planet
• The Pan-Pacific Planet Search VII: The most eccentric planet orbiting a giant star
• A PSF-based approach to Kepler/K2 data - III. Search for exoplanets and variable stars within the open cluster M 67 (NGC 2682)
• Dynamical and Observational Constraints on Additional Planets in Highly Eccentric Planetary Systems
• Catalog of New K2 Exoplanet Candidates from Citizen Scientists
• The GALAH survey: unresolved triple Sun-like stars discovered by the Gaia mission

Cited by in corpus (8)

• The GALAH+ Survey: Third Data Release
• Rapid Formation of Jupiter and Wide-Orbit Exoplanets in Disks with Pressure Bumps
• 37 New Validated Planets in Overlapping K2 Campaigns
• Characterisation of 92 Southern TESS Candidate Planet Hosts and a New Photometric [Fe/H] Relation for Cool Dwarfs
• Another super-dense sub-Neptune in K2-182 b and refined mass measurements for K2-199 b and c
• The NEID Earth Twin Survey. II. Dynamical Masses in Seven High-acceleration Star Systems
• The GALAH Survey: Improving our understanding of confirmed and candidate planetary systems with large stellar surveys
• A Spectroscopic Analysis of a Sample of K2 Planet-Host Stars: Stellar Parameters, Metallicities and Planetary Radii