We observed the North-East ( NE ) Limb toward the center region of the Cygnus Loop with the ASCA Observatory .
In our previous paper ( Miyata et al .
1994 ) , we analyzed the data obtained with the X-ray CCD cameras ( SISs ) .
We found a radial variation of electron temperature ( kT _ { e } ) and ionization timescale ( log ( \tau ) ) whereas no variation could be found for the abundances of heavy elements .
In this paper , we re-analyzed the same data set and new observations with the latest calibration files .
Then we constructed the precise spatial variations of kT _ { e } , log ( \tau ) , and abundances of O , Ne , Mg , Si , and Fe over the field of view ( FOV ) .
We found a spatial variation not only in kT _ { e } and in log ( \tau ) but also in most of heavy elements .
As described in Miyata et al .
( 1994 ) , values of kT _ { e } increase and those of log ( \tau ) decrease toward the inner region .
We found that the abundance of heavy elements increases toward the inner region .
The radial profiles of O , Ne , and Fe show clear jump structures at a radius of 0.9 R _ { s } , where R _ { s } is the shock radius .
Outside of 0.9 R _ { s } , abundances of all elements are constant .
On the contrary , inside of 0.9 R _ { s } , abundances of these elements are 20–30 % larger than those obtained outside of 0.9 R _ { s } .
The radial profile of kT _ { e } also shows the jump structure at 0.9 R _ { s } .
This means that the hot and metal rich plasma fills the volume inside of 0.9 R _ { s } .
We concluded that this jump structure was the possible evidence for the pre-existing cavity produced by the precursor .
If the ejecta fills inside of 0.9 R _ { s } , the total mass of the ejecta was roughly 4 \hskip { 1.422638 pt } M _ { \odot } .
We then estimated the main-sequence mass to be roughly 15 \hskip { 1.422638 pt } M _ { \odot } , which supports the massive star in origin of the Cygnus Loop supernova remnant and the existence of a pre-existing cavity .