A new prescription for the spectral properties of population III stellar populations Marie Lecroq, Stéphane Charlot, Alessandro Bressan, Gustavo Bruzual, Guglielmo Costa, Giuliano Iorio, Michela Mapelli, Filippo Santoliquido, Kendall Shepherd and Mario Spera A&A, 695 (2025) A17 Published online: 27 February 2025 DOI: 10.1051/0004-6361/202452463