Absorption depth in 43 km s^-1 band widths (histogram), as measured around the Mg ii doublet at  ~ 2800 Å by using orbit #2 and #5 as the out-of-transit reference. The absorption depth is averaged over the two Mg ii lines. The absorption depth in the stellar continuum (dashed horizontal line) is measured using the two sides of the Mg ii doublet (from  − 3000 to  − 1000 km s^-1 and from +1000 to +3000 km s^-1).