SIMBAD references

We derive a new mass estimate for the ejecta of the young supernova remnant Cas A of M∼4M_☉, based on X-ray observations with ASCA. The estimated mass is about a third of previous estimates. The total X-ray emitting mass is ∼14M_☉ indicating that the progenitor had a very high mass loss rate. The X-ray spectrum is consistent with the assumption that oxygen is the most abundant element of the ejecta. We also report a puzzling neon and magnesium deficit and the need for a line broadening mechanism. The line broadening is tentatively interpreted as due to an expanding shell. We confirm the presence of position dependent radial bulk velocities found by Markert et al. (1983).