Revised position of Schulte 12 in the Hertzsprung-Russell diagram adopting the distance corresponding to the Gaia-DR2 parallax. The evolutionary tracks are taken from Ekström et al. (2012) for solar metallicity and no rotation. The continuous red line corresponds to the empirical Humphreys–Davidson limit (Humphreys & Davidson 1994). Various instability boundaries are shown according to Saio (2011). The dotted red curve indicates the instability boundary of low-order radial and non-radial p-mode oscillations. The short-dashed magenta contour indicates the region where non-radial g-modes with ℓ ≤ 2 are excited by the iron opacity bump. Finally, the cyan long-dashed contour indicates the region where oscillatory convection modes with ℓ ≤ 2 are excited (Saio 2011).