Reduced SPHERE images of Wray 15-788. All frames show the same region on the sky with a field of view of approximately 1.′′39 × 1.′′39. The star is positioned in the center of each image. An artificial mask with a diameter of ~ 196 mas is applied to obscure the coronagraph and leaking flux close to it. The images are scaled with r² according to the deprojected separation of the disk to star in the center of the image. The scaling is corrected for an inclination of 21° and a position angle of 76°, as derived in Sect. 5.3.1. In each image north is up and east is left. An arbitrary linear color scale is applied, which is normalized to the maximum flux in each frame. Panels a and b: results obtained with SPHERE in CI mode applying a broad H- and K_s -band filter, respectively. The stellar point spread function was reconstructed by a fit of 20 principal components obtained from a library of reference stars. In the bottom panel we present the results obtained from SPHERE DPI data in H band. Panels c and d: Stokes Q and U parameters for linear polarization, respectively. Both polarimetric results are smoothed with a Gaussian kernel having a FWHM of ~50 mas. This is equivalent to the theoretical SPHERE FWHM in H band.