Further analysis of X-ray spectroscopy results ( Willingale et al .
2002 ) recently obtained from the MOS CCD cameras on-board XMM-Newton provides a detailed description of the hot and cool X-ray emitting plasma in Cas A .
Measurement of the Doppler broadening of the X-ray emission lines is consistent with the expected ion velocities , \sim 1500 km s ^ { -1 } along the line of sight , in the post shock plasma .
Assuming a distance of 3.4 kpc , a constant total pressure throughout the remnant and combining the X-ray observations with optical measurements we estimate the total remnant mass as 10 M _ { \sun } and the total thermal energy as 7 \times 10 ^ { 43 } J .
We derive the differential mass distribution as a function of ionisation age for the hot and cool X-ray emitting components .
This distribution is consistent with a hot component dominated by swept up mass heated by the primary shock and a cool component which are ablated clumpy ejecta material which were and are still being heated by interaction with the preheated swept up material .
We calculate a balanced mass and energy budget for the supernova explosion giving a grand total of 1.0 \times 10 ^ { 44 } J in an ejected mass ; approximately \sim 0.4 M _ { \sun } of the ejecta were diffuse with an initial rms velocity \sim 1.5 { \times } 10 ^ { 4 } km s ^ { -1 } while the remaining \sim 1.8 M _ { \sun } were clumpy with an initial rms velocity of \sim 2400 km s ^ { -1 } .
Using the Doppler velocity measurements of the X-ray spectral lines we can project the mass into spherical coordinates about the remnant .
This provides quantitative evidence for mass and energy beaming in the supernova explosion .
The mass and energy occupy less than 4.5 sr ( < 40 % of the available solid angle ) around the remnant and 64 % of the mass occurs in two jets within 45 degrees of a jet axis .
We calculate a swept up mass of 7.9 M _ { \sun } in the emitting plasma and estimate that the total mass lost from the progenitor prior to the explosion could be as high as \sim 20 M _ { \sun } .
We suggest that the progenitor was a Wolf-Rayet star that formed a dense nebular shell before the supernova explosion .
This shell underwent heating by the primary shock which was energized by the fast diffuse ejecta .