Mass-per-charge spectra of heavy pickup ions obtained by PLASTIC on STEREO A for three different time periods in which either O⁺, C⁺, or Ne⁺ show a significantly increased abundance compared to other heavy pickup ions (panels from left to right respectively). These periods were used to obtain the necessary parameters for the mass-per-charge model (Eq. (2)) that is used to obtain the heavy pickup ion w_sw-spectra.