Stress-Testing Substellar Models with a Uniform Analysis of Transiting Brown Dwarf Ages

Models of substellar evolution are critical for a wide range of exoplanet science, such as inferring masses of directly imaged planets. Testing these models requires knowledge of masses, radii, and ages, which cannot be independently constrained for directly imaged planets and brown dwarfs. The population of transiting brown dwarfs has almost tripled over the past five years thanks to NASA’s TESS Mission, now enabling a systematic test of substellar models from the mass, radius, and age measurements obtained from transiting brown dwarfs. Previous results demonstrate that both low-mass (13-25 Jupiter masses) and high-mass (70-75 Jupiter masses) brown dwarfs show clear signs of radius inflation with respect to substellar models, but it is unclear which inflation mechanisms are at play and whether or not these inflation mechanisms are shared between low- and high-mass brown dwarfs. A solution to understand these discrepancies is to determine robust ages for these objects via age dating of their host stars, which is now possible through a combination of techniques such as isochrone fitting, asteroseismology, and gyrochronology. I will present results from the first uniform transit, radial velocity, and host star age analysis of the largest number of transiting brown dwarf host stars to date. In addition to a uniform analysis of ages, this work also includes a homogeneous analysis of brown dwarf masses and radii made possible through the TESS mission and precise photometry and astrometry from the Gaia mission. First results show that, at a given mass, substellar models predict the age-radius evolution of intermediate-mass (40-65 Jupiter mass) brown dwarfs accurately at young ages, but perform poorly at ages beyond 1 Gyr. These results also show that radius inflation persists in low-mass and high-mass brown dwarfs, resulting in poor agreement with models.