On the Orbital Inclination of Proxima Centauri b

Abstract

The field of exoplanetary science has seen discovery rates increase dramatically over recent years, due largely to the data from the Kepler mission. Even so, individual discoveries of planets orbiting nearby stars are very important for studies of characterization and near-term follow-up prospects. The recent discovery of a terrestrial planet candidate orbiting Proxima Centauri presents numerous opportunities for studying a Super-Earth within our own stellar backyard. One of the remaining ambiguities of the discovery is the true mass of the planet since the discovery signature was obtained via radial velocities. Here we describe the effect of orbital inclination on the Proxima Centauri planet, in terms of mass, radius, atmosphere, and albedo. We calculate the astrometric, angular separation, and reflected light properties of the planet including the effects of orbital eccentricity. We further provide dynamical simulations that show how the presence of additional terrestrial planets within the Habitable Zone varies as a function of inclination. Finally, we discuss these effects in the context of future space-based photometry and imaging missions that could potentially detect the planetary signature and resolve the inclination and mass ambiguity of the planet.