Exploring the range of impacts of helium in the spectra of double detonation models for Type Ia supernovae. - Callan, F P; Collins, C E; Sim, S A; Shingles, L J; Pakmor, R; Srivastav, S; Pollin, J M; Gronow, S; Röpke, F K; Seitenzahl, I R (Monthly Notices of the Royal Astronomical Society, 2025)