A supernova explosion is a catastrophic event that a star experiences at the end of its life, especially a thermonuclear supernova, which usually represents the complete destruction of a white dwarf star, leaving nothing behind. So when astronomers observed the thermonuclear supernova SN 2012Z, they were shocked to find that the star survived the explosion and even became brighter than before.
According to the physical mechanism of supernova explosion, it can be mainly divided into two categories: thermonuclear supernova and core-collapse supernova. Their explosion mechanisms are completely different. The former comes from “white dwarf-white dwarf” or “white dwarf-red giant star” “Binary star systems explode, the latter from explosions caused by unstable core collapses at the end of the evolution of a single massive star.
Thermonuclear supernovae, also known as Type Ia supernovae, are one of the most important objects that astronomers use to measure distances in the universe. Past observations of these explosions have shown that the universe has been expanding at an accelerating rate. Under Type Ia supernovae, there are also “Type Iax supernovae” subs Deformed, fainter and weaker than Type Ia supernovae, with less powerful and slower explosions, but this type of supernova may not completely destroy the predecessor white dwarf, some scientists believe they are failed Type Ia supernovae, now new observations confirm this assumption.
In 2012, astronomers discovered the SN 2012Z supernova event in the nearby spiral galaxy NGC 1309, and used the Hubble Space Telescope to conduct follow-up investigations to try to find the star that preceded the explosion. When the latest data was available, the UC Santa Barbara team was expecting to see To two phenomena, one is the complete disappearance of the star, which is also the most plausible result; the other is that there are still stars there, indicating that the star seen in the image before the explosion was not the party of the explosion.
But no one expected to see a surviving star that pretended to be dead and turned brighter.
The researchers say that the Iax-type supernova explosion may not be strong enough to blow away all the matter, as if it just stirred up the gas, so the star exploded but did not die, and even became more inflated. Over time, the star is expected to Slowly return to the original state. It is still the same star, but in a different form standing there, like a representation of beyond death.
Now, astronomers need to understand how a Type Ia supernova fails to become a Type Iax supernova. The new paper is published in The Astrophysical Journal.
(The first picture shows the galaxy NGC 1309, source: NASA)
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