2025AJ....169..234J

Several planet formation models have been proposed to explain the gap in the population of planets between 1.8R_⊕ to 2.0R_⊕ known as the “radius valley.” To apply these models to confirmed exoplanets, accurate and precise host-star and planet parameters are required to ensure the observed measurements correctly match model predictions. Previous studies have emphasized the need for a larger, more precise sample to further confirm dominant formation processes. By enhancing standard spectral energy distribution fitting using Bayesian methods, we derived highly accurate and precise host-star and planet parameters. Specifically, we achieved median fractional uncertainties for stellar and planet radii of 2.4% and 3.4%, respectively. We then produced the largest, most precise sample to date of 1923 planets when compared to previous studies. This full sample, as well as a sample filtered for host stellar masses between 0.8 and 1.2M_⊙, were then used to derive the slope and position of the radius valley as a function of orbital period, insolation flux, and stellar mass to compare them to predictive models and previous observational results. Our results are consistent with thermally driven mass loss with a planet radius versus orbital period slope of ${R}_{p}={P}^{{-0.142}_{-0.006}^{+0.006}}{e}^{{0.896}_{-0.010}^{+0.012}}$ for the full sample, leaning toward core-powered mass loss. The planet radius versus insolation flux slope of ${R}_{p}={{S}_{p}}^{{0.136}_{-0.014}^{+0.014}}{e}^{{-0.085}_{-0.030}^{+0.031}}$ for the filtered sample leaned toward photoevaporation. Also, the slope as a function of stellar mass for both samples appears more consistent with thermally driven processes when compared to models and previous studies.