Erratum: Molecules with ALMA at Planet-forming Scales (MAPS). III. Characteristics of Radial Chemical Substructures (Astrophysical Journal, Supplement Series (2021) 257 (3) DOI: 10.3847/1538-4365/ac1434)

In the published article, we computed the disk size in 18 molecular emission lines and the 90 and 260 GHz continuum for all sources (Section 3.5). We defined R_gasas the radius which encloses 90% of the total line emission or continuum flux. However, we omitted the necessary factor of 2πr when computing the cumulative sums, i.e., the integral of a radial function has an areal element of 2πrdr. Table 2 is revised and lists the updated gas and continuum disk sizes, and Figures 15 and 16 are also updated. For all sources, the disk size of each line increases in nearly all cases, with mean increases of 45% (IM Lup), 47% (GM Aur), 22% (AS 209), 44% (HD 163296), and 43% (MWC480). The most notable changes are ≳100% increases in the continuum sizes of the IM Lup and MWC480 disks. The continuum emission in the AS 209 disk is no longer smaller than the majority of lines, and instead it is slightly larger than the complex nitriles and comparable to that of C₂H 3-2 and CS 2-1. Overall, the relative ordering of disk sizes among lines remains approximately the same, as shown in Figures 15 and 16, and all subsequent discussion and conclusions presented in the published article remain unchanged.