Exoplanet Populations, Kepler, Hierarchical Bayesian models, Approximate Bayesian Computing, Machine Learning, Gaussian Process Emulators
Here we report the sizes and masses of three planets orbiting Kepler-138, a star much fainter and cooler than the Sun. We determine that the mass of the Mars-sized inner planet, Kepler-138 b, is $0.066^{+0.059}_{-0.037}$ Earth masses. The middle and outer planets are both slightly larger than Earth...