Absorption depth in 43 km s^-1 band widths (histogram), as measured around the Mg i line by using only the orbit #2 as the out-of-transit reference. The absorption depths measured in the stellar continuum in the +500 to +2500 km s^-1 range (red side continuum, red dot-dashed line) and in the  − 2500 to  − 500 km s^-1 range (blue side continuum, blue dashed line) are also shown. The AD^′Total absorption depth is measured to be 8.8    ±    2.1% in the velocity domain from  − 67 to  − 19 km s^-1.