  Thermonuclear (Type Ia) supernovae are bright stellar explosions, the light
curves of which can be calibrated to allow for use as "standard candles" for
measuring cosmological distances. Contemporary research investigates how the
brightness of an event may be influenced by properties of the progenitor system
that follow from properties of the host galaxy such as composition and age. The
goals are to better understand systematic effects and to assess the intrinsic
scatter in the brightness, thereby reducing uncertainties in cosmological
studies. We present the results from ensembles of simulations in the
single-degenerate paradigm addressing the influence of age and metallicity on
the brightness of an event and compare our results to observed variations of
brightness that correlate with properties of the host galaxy. We also present
results from "hybrid" progenitor models that incorporate recent advances in
stellar evolution.
