Origin of the shrapnels around the Vela SNR

There are several shrapnels around the Vela SNR that originated from the inner layer of the progenitor star. We present here the analysis of the X-ray spectrum of the Vela shrapnel A with XMM-Newton satellite. The Vela shrapnel A is one of several protrusions identified as bullets from Vela supernova explosion. We confirmed that there was a prominent Si Kα emission line showing a Si-rich plasma. The mass ratio between O and Si is 1.4:1. The shrapnel D also shows metal rich abundance. The mass ratio of O, Ne and Mg is about 7:3:1. These mass ratios can be found in the 13M⊙ star. We estimate that the birth place of the shrapnel A is the mass radius of 1.5M⊙ while that of the shrapnel D is the mass radius of 1.64M⊙.