Stars showing narrow non-photospheric absorptions. Top panels: photospheric Ca II H & K and Na I D lines with fitted modelling, the blue-dashed line, x-axis shows the wavelength. Bottom panels: residuals once the spectrum was divided by the photosphere, x-axis in velocity. Blue lines mark the fits to the non-photospheric absorptions. Vertical red-dashed and grey dotted-lines represent the stellar radial velocity and the ISM velocities, respectively. The red error bars show three sigma values measured in the continuum adjacent to the photospheric line.