We are used to seeing spectacular images from supernovae, but NASA might have just one-upped all of them with the first ever video of a supernova remnant.
The object, called SN 1572, is a well-known and well-studied supernova, so NASA was able to combine optical observations, 16 years of data from its Chandra X-ray Observatory with 30 years of data from the Very Large Array. With this, they created an animation of the supernova remnant expanding at up to 5,000 kilometers per second (12 million mph). It is located between 8,000 and 9,800 light-years from Earth in the constellation of Cassiopea.
SN 1572 is also known as Tycho’s supernova, named after astronomer Tycho Brahe who extensively described it in his work in the 16th Century. He was not the first one to observe it, however, as it was visible to the naked eye, and had fascinated astronomers since 1572.
The video is not only very beautiful to look at, but it also contains very valuable physics information about the state of the system. Astronomers were able to precisely calculate the rate of expansion at different locations around the object and were surprised that, although SN 1572 is circular, the speed of the material in the right/lower-right corner is twice as fast as the material in the upper-left/left.
When the supernova exploded, it launched material into space compressing the interstellar material at speed 1000 faster than the speed of sound. This heats up the material and makes it shines in x-rays which are picked up by Chandra.
The expansion of SN 1572 from 2000 to 2015. NASA/CXC/GSFC/B.Williams et al/DSS
Although the material ejected from the star has been expanding for 444 years, the velocity discrepancy is a recent phenomenon and it’s due to the different density of materials surrounding Tycho’s supernova. In the first few hundred years, the shock was so energetic that the difference in density didn’t matter, but it is has become significant now.
By measuring the velocities, the team was able to discover that the center has been displaced towards the upper left from the geometric center by about 10 percent of the remnant's radius. These results, accepted for publication in the Astrophysical Journal Letter, will help astronomers hunt for the potential presence of a companion star.
A surviving companion could provide vital information to understand what type of supernova SN 1572 was. It was established that the progenitor was a white dwarf, but these stars can go supernova either by stealing material from a companion or by merging with a fellow white dwarf. As white dwarf supernovae are used to estimate how far away distant galaxies are, studying Tycho’s supernova might hopefully help us unlock the secrets of the universe as a whole.