γ-ray astronomy from the Cas A remnant. We investigate in the laboratory the major 44Ti production reaction 40Ca(α,γ)44Ti (Ec.m.∼0.6–1.2
MeV/u) by direct off-line counting of 44Ti nuclei. The yield, significantly higher than inferred from previous experiments, is analyzed in terms of a statistical model using microscopic nuclear inputs. The associated stellar rate has important astrophysical consequences, increasing the calculated supernova 44Ti yield by a factor ∼2 over previous estimates and bringing it closer to Cas A observations.