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