Zombie Stars - What are they and how do they exist?

What are zombie stars and how do they form?  

Zombie stars are stars in the universe that explode in a supernova, but for some reason, they just don’t behave like a normal supernova and they don’t die.  Typically, a supernova tends to obliterate the white dwarf and/or dying star. In the case of zombie stars, the supernova in considerably weaker than a normal supernova and they will leave behind a surviving portion of the zombie star. In some instances, this star has exploded into a second supernova.  One way that zombie stars form would be in binary star systems, where one star is larger than the other; the smaller star will then become a vampire star and start sucking the gas from the bigger star until all that is left is a core known as a white dwarf.  What will happen next is due to the fact that now the smaller star has become considerably more massive. The white dwarf will now begin to suck gas from the big star until, in a sort of revenge, the zombie white dwarf will explode into a supernova.  These zombie stars are actually surprisingly common throughout our universe; a recent example of these zombie stars occured in 2014, when the star iPTF1hls exploded for the second time. 

The first known time this star exploded was in 1954, and only 40 years later, the explosion from 1954 was unseeable. In 2014, this star exploded again and scientists have been studying it ever since.

You can find more information about these fascinating stars here.

Sources:

• Source 1

Post created by Matthew