Calculations of the atomic parameters for the dielectronic satellite lines of the Mg XII resonance line

New calculations of the atomic parameters for the dielectronic satellites of the Mg XII resonance lines 1s–2p, 1s–3p, 1s–4p, have been performed in a multiconfiguration intermediate coupling scheme. The satellite lines correspond to transitions of the type $$1s \,nl-n^{\prime} l^{\prime} n^{\prime\prime} l^{\prime\prime}$$ for $$n, n^{\prime}, n^{\prime\prime} = 2, 3 \,\text{and} \,4.$$ The effect on the satellite level population of cascades from higher excited levels is discussed and the cascade correction for the relative intensity ratio of the satellite to resonance line is derived. Comparison is made with previous calculations for n = 2 satellites, Vainshtein & Safronova (1978).