Emitted decay power as a function of time since explosion in model s15p2 (see Table 1 for the yields). We show the individual contributions from the dominant unstable isotopes (the label refers to the parent isotope of the two-step decay chains) as colored curves, with the total given by the black dashed curve. Because of γ-ray escape, the power effectively absorbed by the ejecta is only a fraction of the power emitted (about 25% at 1000 d in this model). The dominant source of power is ⁵⁶Ni in the first 1000 d, while ⁴⁴Ti takes over beyond about 3000 d. Evidently, ejecta interaction with a standard RSG wind, which delivers a power of about 10⁴⁰ erg s⁻¹ would dominate over radioactive decay after about 600 d.