Preponderance of perpendicular planets. Measurements of the 3D obliquity, ψ, from Albrecht et al. (2021) shown as circles with colour coding according to ψ. Recent ψ measurements not in Albrecht et al. (2021) are shown as stars, including TOI-640 (red outline). Left: ψ as a function of effective temperature. Middle: ψ as a function of planet-to-star mass ratio. Right: ψ as a function of orbital separation. It is worth noting that here we are only considering the results for ψ corresponding to i (and not 180° – i).