X-ray data from the Chandra observatory has shed new light on the origin of “Kepler’s Supernova”, first seen in 1604 by Johannes Kepler himself.
Kepler’s Supernova is actually a supernova remnant – a large cloud of expanding gases left behind after a supernova has exploded. The false colour image above is actually composed entirely of X-ray data: low, intermediate and high energy X-rays in red, green and blue respectively.
We know that Kepler’s Supernova was what Astronomers call a Type 1a Supernova – one of a binary pair of stars (always a dense white dwarf star at the end of its life) explodes. There’s been a bit of a disagreement over the exact mechanism behind this kind of supernova, whether they are produced by two white dwarf stars colliding into each other as a result of their increased densities altering their attraction to each other, or whether one white dwarf star sucks so much material from its companion star (whatever kind it may be) that it becomes unstable and explodes shortly thereafter.
A study published in February this year seems to discredit the first possibility. Using data from the Chandra observatory, researchers were able to determine that Kepler’s supernova was produced by one white dwarf becoming unstable after sucking too much material off of a companion red giant star.
The expanding cloud of material left behind is distinctly iron-rich on only one side of the cloud, around a disc-like structure that the researchers speculate could be debris from the explosion. They postulate that the iron is only present in one side of the nova because of the influence of the red giant star shielding some of the blast of the supernova – if only for a few seconds.
The study was originally published in the February 10th edition of the Astrophysical Journal Letters.
Image: False colour X-ray image of Kepler’s Supernova. Credit: NASA/CHANDRA