Average absorption depth (AAD) variations in the Ca II circumstellar line region 0 ± 5 km s⁻¹. In blue, the K-line AAD and in red the H-line. They are compared to the total Fe I ground level column density variations in Table 4. The marker size is proportionnal to the number of nights where β Pic was observed by HARPS in each period (see Table 1). For the sake of comparison, the Fe I column densities arescaled to the Ca II AAD median.