Comparison between the thermalization radius (r_te; Eq. (21)) and the stellar core radius (r_★c). When the cross section is small (σ₀/m  =  0.3 cm² g⁻¹; the cyan lines), then r_te and r_c are similar, particularly in the region of interest for UFDs, where M_★ < 10⁶ M_⊙. On the contrary, r_te ≫ r_★c for large cross sections (σ₀/m  =  400 cm² g⁻¹; the lemon yellow lines). For reference, the characteristic radius of the original NFW (r_s; the dotted red line) and the virial radius (r_vir; the dotted-dashed red line) are included.