Modeled planet, star, and total intensities, photocenter and FWHM spectra (from top to bottom) when the slit is oriented close to the planet’s position and close to perpendicular (left and right panels, respectively). The black line refers to the fiducial values for LkCa 15 (see caption in Fig. C.2), with s = 110 mas, α = 8° (left), and 82° (right). The colored lines refer to variations in s (red) and α(blue) within error bars (dotted and dashed lines for the corresponding upper and lower limits; see text). The horizontal dashed lines in the photocenter panels represent our detection limits. The FWHM spectra plotted are ~1 order of magnitude below detection limits.