Scientists have studied the supernova remnant G278.94+1.35. It is much closer than previously thought. The event that produced it happened about a million years ago.
Supernova remnant not far from Earth
An international team of astronomers has studied a large galactic supernova remnant, designated G278.94+1.35. The findings, published on December 30 on the arXiv preprint server, shed more light on the properties of this residue.
Supernova remnants (SNRs) are diffuse structures that expand as a result of a supernova explosion. They contain ejected material expanding from the explosion and other interstellar material that has been picked up by the shock wave from the exploded star.
G278.94+1.35 is a supernova remnant in the Milky Way discovered in 1988. It has a linear diameter of about 320 light-years and an age of about 1 million years. The distance to G278.94+1.35 is estimated to be about 8,800 light-years.
A team of astronomers led by Miroslav D. Filipovic from the University of Western Sydney in Australia recently made observations with the Australian Square Kilometer Array Pathfinder (ASKAP) telescope as part of the ASKAP-Evolutionary Map of the Universe (EMU) project. During these observations, they accidentally discovered a large-scale object that was identified as G278.94+1.35.
Remnant dimensions G278.94+1.35 and its designation
According to the paper, ASKAP-EMU images show that G278.94+1.35 has an angular size of at most 200 by 194 angular minutes, corresponding to a diameter of 512 by 495.5 light-years. However, further research has shown that G278.94+1.35 is located at a much closer distance than previously thought — about 3,300 light-years away. This indicates that its physical size is smaller than previously thought. This indicates that its physical size is 189 x 182 light years.
Filipovic’s team named G278.94+1.35 “Diprotodon,” after an extinct genus of Australian marsupials from the Pleistocene period that resembled a giant wombat.
“We took this name for G278.94+1.35 to raise awareness of this extinct Australian animal and the entire prehistoric megafauna of Australia, as well as to raise awareness of the current rate of extinction of several other species in Australia. Since G278.94+1.35 is potentially one of the largest supernova remnants, it is appropriate to compare it to the largest of the wombats, Diprotodon,” the astronomers explain.
Characteristics of Diprotodon
In addition, the study showed that Diprotodon is in the radiative stage of evolution. Its almost circular shape, observed in such a large field of view, indicates that the remains are still expanding.
Based on the data collected, the authors of the paper estimate that the mass of the ancestor of Diprotodon is about 15 solar masses and the kinetic energy of the SNR is at 500 quindecillion erg. The measured spectral index of the remnant was approximately -0.55, which is representative and common for the average remnants of shell-type supernovae observed in the Milky Way.
According to phys.org
