摘要：Recently, several groups have resolved a gap that bifurcates planets between the size of Earth and Neptune into two populations. The location and depth of this feature is an important signature of the physical processes that form and sculpt planets. In particular, planets residing in the radius gap are valuable probes of these processes as they may be undergoing the final stages of envelope loss. Here, we discuss two views of the radius gap by Fulton & Petigura (F18) and Van Eylen et al. (V18). In V18, the gap is wider and more devoid of planets. This is due, in part, to V18ʼs more precise measurements of planet radius Rp. Thanks to Gaia, uncertainties in stellar radii R* are no longer the limiting uncertainties in determining Rp for the majority of Kepler planets; instead, errors in Rp/R* dominate. V18ʼs analysis incorporated short-cadence photometry along with constraints on mean stellar density that enabled more accurate determinations of Rp/R. In the F18 analysis, less accurate Rp/R*blurs the boundary the radius gap. The differences in Rp/R* are largest at high impact parameter (b >0.8) and often exceed 10%. This motivates excluding high-b planets from demographic studies, but identifying such planets from long-cadence photometry alone is challenging. We show that transit duration can serve as an effective proxy, and we leverage this information to enhance the contrast between the super-Earth and sub-Neptune populations.
