Orbital inclination and mass of the exoplanet candidate Proxima c

We analyze the orbital parameters of the recently discovered exoplanet candidate Proxima c using a combination of its spectroscopic orbital parameters and Gaia DR2 astrometric proper motion anomaly. We obtain an orbital inclination of i=152 +/- 14 deg, corresponding to a planet mass of textual-form specific-use=web-only m(c) = 12(-5)(+12)M(circle plus) m c = 12 - 5 + 12 mml:msubsup mml:mspace width=0.166667emmml:mspace mml:msub M circle plus comparable to Uranus and Neptune. While the derived orbital parameters are too uncertain to accurately predict the position of the planet for a given epoch, we present a map of its probability of presence relative to its parent star in the coming years.