The ROSAT all-sky survey discovered several ‘ shrapnels ’ , showing boomerang structures outside the Vela supernova remnant .
We observed shrapnel D with the XMM-Newton satellite .
There is an X-ray bright ridge structure in our FOV running from north to south .
Applying the VNEI model to X-ray spectra of various regions , we find that the plasma in the eastern part from the X-ray ridge is significantly different from that in the western part .
The X-ray spectra in the western part can be represented by a single-temperature component .
The abundances of heavy elements are almost uniform , whereas they are heavily overabundant , except for Fe ; the relative abundances to the solar values are O \sim 5 , Ne \sim 10 , Mg \sim 10 , Fe \sim 1 .
This indicates that shrapnel D originated from the ejecta of the supernova .
We find that the plasma in the eastern part from the ridge consists of two components with different temperatures ; the hot component comes from the ejecta , while the cold component comes from the interstellar matter .
These two components are considered to be in contact with each other , forming a contact discontinuity .
Around the northern part of the contact discontinuity , we find wave-like structures of which the typical scale are comparable with that of the Rayleigh–Taylor instability .