  This thesis is devoted to the analysis of X-ray observations of supernova
remnants (SNRs), exploiting the diagnostic potential provided by X-ray
spectroscopy and complementing it with the synthesis of X-ray observables from
multi-dimensional hydrodynamic (HD) and magneto-hydrodynamic (MHD) models. I
tackle three open issues: the search for a spectral signature to correctly
recover abundance and mass values of the stellar fragments ejected in the SN
explosion through their X-ray spectra; the study of anisotropies and the origin
of overionized plasma in the mixed-morphology SNR IC 443; the quest for the
elusive compact object in SN 1987A.

High Energy Astrophysical Phenomena