An article published in the journal “Astronomy & Astrophysics” describes an analysis of the chemical composition of a kind of plasma shrapnel ejected from the Vela supernova remnant (bottom image ©Harel Boren). A team led by Federico García of the Argentinian Institute of Radioastronomy used the XMM-Newton Space Telescope to study the plasma jets around the the supernova remnant discovering an abnormal abundance of silicon.
The Vela supernova remnant is what remains after a supernova approximately 800 light years from Earth. The progenitor star probably exploded between 11,000 and 12,000 years ago generating a nebula and leaving its core in the form of a neutron star called the Vela Pulsar. Studying supernova remnants can provide information to better understand the stars that exploded and the catastrophic events in which they died.
This study of the Vela supernova remnant focused on the shrapnel made up of pieces of materials ejected from the supernova. The composition of these shrapnel was curious because one of them, indicated by letter A in the image above, shows a high silicon abundance in the X-ray spectrum and this contrasts with that of most other shrapnel, which show a rich content of oxygen, neon and magnesium.
Another exception is the shrapnel indicated by the letter G in the image above, an interesting fact because the two very high silicon shrapnel are in a mirrored position with respect to the supernova center. According to the researchers, their characteristics are evidence that they’re made of plasma ejected from regions deep within the progenitor star in the form of two jets launched in directions opposite with respect to the supernova’s expansion center.
The Vela supernova remnant is an ideal candidate to conduct an analysis of that kind of shrapnel due to its age and its position with respect to Earth. In fact, structures such as those observed within it have been discovered in just a few other supernova remains and this increases their importance.
The XMM-Newton Space Telescope allowed to observe portions of the Vela supernova remnant at X-rays to gather information on the collapse of the progenitor’s core and the shrapnel formation, processes of which there’s still a limited understanding. The researchers hope to conduct new observations when the Russian SRG Space Telescope, also known as Spektr-RG (Spektrum-Roentgen-Gamma), is launched, as it would allow to observe the whole remnant.