H-band intensity in all of our simulations, taken at fiducial radii r_inner,cut = 30 au and r_outer,cut = 60 au, and normalized to the azimuthal average. The 3T simulations show a clear m = 2 spiral with a peak-to-trough intensity ratio ~4 in the outer disk and ~ 1.2–1.5 in the inner disk. By contrast, the β-cooling simulations show negligible asymmetry in the outer disk, alongside asymmetries of ~ 1.1–1.5 in the inner disk caused by inner Lindblad spirals.