Line profiles of Si III 4551 obtained on JD 2 451 655 corrected for the orbital motion of m₁ using the measured RVs from Table A.3. These spectra cover a timespan of 8.67 h and correspond to the orbital phase range 0.34–0.43. The m₂ absorption is centered on −280 km s^-1 in this reference frame. Each profile is shifted along the ordinate by a fixed amount for display purposes, with time running from bottom to top.