HD 39060 (β Pic) major axis profile (top) from the south (minus major axis direction) to the north (positive radial direction), and its associated major axis difference profile about the image centre (bottom). We show in red and green dash-dot lines ±3σ and ±5σ profile differences, and in amber the error associated with the difference profile, scaled by $\sqrt{2}$ to account for the uncertainty in the self-subtraction of the profile. We also show the ≈85 au radial location (in blue) associated with β Pic’s known CO clump from Dent et al. (2014).