Title: Pinning down the mass of Kepler-10c: the importance of sampling and model comparison,
Abstract: Initial RV characterisation of the enigmatic planet Kepler-10c suggested a
mass of $\sim17$ M$_\oplus$, which was remarkably high for a planet with radius
$2.32$ R$_\oplus$; further observations and subsequent analysis hinted at a
(possibly much) lower mass, but masses derived using RVs from two different
spectrographs (HARPS-N and HIRES) were incompatible at a $3\sigma$-level. We
demonstrate here how such mass discrepancies may readily arise from sub-optimal
sampling and/or neglecting to model even a single coherent signal (stellar,
planetary, or otherwise) that may be present in RVs. We then present a
plausible resolution of the mass discrepancy, and ultimately characterise
Kepler-10c as having mass $7.37_{-1.19}^{+1.32}$ M$_\oplus$, and mean density
$3.14^{+0.63}_{-0.55}$ g cm$^{-3}$.