Outcomes given ejecta accumulation only along Didymos’s equator, which makes a hypothetical pile of the accumulated ejecta on an elliptical hoop. Panel (a) displays the thickness change at the equator after spin-driven reshaping (Modification II), which is similar to the distribution of Δt_r in Figure 4. On the other hand, panel (b) shows the mutual orbit period change in seconds due to Didymos’s shape change process that includes both DART-ejecta accumulation and spin-driven shape change, which is similar to Figure 6.