Top: residuals of the Q_ϕ image after subtraction of the model of scattering by the disk of WRAY 15-1880, projected on the disk plane. The small red circle represents the position of the star; the small magenta circle the position of the candidate planet discovered on the SPHERE high-contrast image; the large magenta dashed circle is a circular orbit passing through its position. Bottom: intensity along the circular orbit from the image in the top panel as a function of the angle ϕ. This is the angle with respect to the star in this plane computed counterclockwise starting from the major axis north of the star. The solid vertical line represents the planet position; the dashed vertical line represents the position of the L4 Lagrangian point.