Evidence of Radius Inflation Based on 50 Transiting Brown Dwarfs and Low-mass Stellar Companions

Statistical assessment of stellar parameters enables validation and improvements in theoretical models. We compiled a sample of 85 transiting stellar and substellar companions, with masses ranging from about 13-100 M Jup. We focus on analyzing 50 transiting companions with robust ages and model constraints, and evaluate the degree of radius inflation versus mass, separation, equilibrium temperature, and metallicity. Our evaluation of the differences between measured and model radii indicates an 8.7 plus or minus1.9 % radius inflation for the full sample, at 4.6 sigma discrepancy, validating the existence of radius inflation at a population level in transiting brown dwarfs. For brown dwarfs at separations at most 0.05 au, we find an even higher radius inflation, with a median inflation of 16 plus or minus6 % at 2.7 sigma, and the inflation decreases toward wider separations, likely due to reduced stellar irradiation. Finally, we provide our compilation for the community to use.