  We calculate the time-dependent metal production expected from starbursts and
use them as boundary conditions in our 2D simulations of evolving superbubbles.
We assume that the produced metals (oxygen and iron) thoroughly mix with the
ejected stellar envelopes, and/or with the matter thermally evaporated from the
superbubble cold outer shell. The metal production process determines the
time-dependent metallicity in hot superbubble interiors, and leads to values of
Z greater or equal than solar, when oxygen is used as tracer, and under-solar
when the metallicity is measured with respect to iron. In either case, the
enhanced metallicity boosts the X-ray emissivity of superbubbles, bringing
theory and observations closer together.
