(a) The mass–radius diagram spanning the regime of substellar companions and convective M dwarfs. The KOIs characterized in this work are shown as red stars, while the published objects are shown as gray circles. A nominal isochrone of 8 Gyr (the median SED age for the 28 KOIs) is plotted for reference. A total of 24 objects are nongrazing and have larger radii than theoretical models predict. The regions shown in panels (b) and (c) are marked with rectangles. (b). The mass–radius diagram for the nine nongrazing KOI companions spanning 30 M _J < M ₂ < 110 M _J. (c) The mass–radius diagram for the 15 nongrazing KOI companions spanning 140 M _J < M ₂ < 250 M _J. The objects in panels (b) and (c) are colored based on the age estimated from the SED fit. Evolutionary tracks for 2 and 8 Gyr from models by Marley et al. (2021; Sonora21), Phillips et al. (2020; ATMO20), Baraffe et al. (1998; BCAH98), and Baraffe et al. (2015; BHAC15) are plotted for reference and use the same color scale as the stars.