2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/169408The Mn to Cr mass ratio in supernova ejecta has recently been proposed as a tracer of Type Ia SN progenitor metallicity. We review the advantages and problems of this observable quantity, and discuss them in the framework of two Galactic supernova remnants: the well known Tycho SNR and W49B, an older object that has been tentatively classified as Type Ia. The fluxes of the Mn and Cr Ka lines in the X-ray spectra of these SNRs observed by the Suzaku and ASCA satellites suggest progenitors of supersolar metallicity for both objects.5 pages, 2 figures, proceedings of the 10th Symposium on Nuclei in the CosmosAstrophysicstext