How Do Supernovae Fail?

Article Updated: 12 Oct , 2016
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We’ve written quite a few articles on what happens when massive stars fail as supernovae. Here’s a quick recap.

A star with more than 8 times the mass of the Sun runs out of usable fuel in its core and collapses in on itself. The enormous amount of matter falling inward creates a dense remnant, like a neutron star or a black hole. Oh, and an insanely powerful explosion, visible billions of light-years away.

There are a few other classes of supernovae, but that’s the main way they go out.

But it turns out some supernovae just don’t bring their A-game. Instead hitting the ball out of the park, they choke up at the last minute.

They’re failures. They’ll never amount to anything. They’re a complete and utter disappointment to me and your mother. Oh wait, we were talking about stars, right.

So, how does a supernova fail?

New research shows that some old stars known as white dwarfs might be held up by their rapid spins, and when they slow down, they explode as Type Ia supernovae. Thousands of these "time bombs" could be scattered throughout our Galaxy. In this artist's conception, a supernova explosion is about to obliterate an orbiting Saturn-like planet.   Credit: David A. Aguilar (CfA)

In this artist’s conception, a supernova explosion is about to obliterate an orbiting Saturn-like planet. Credit: David A. Aguilar (CfA)

In a regular core collapse supernova, the infalling material pushes the star denser and denser until it reaches the density of 5 billion tons per teaspoon of matter. The black hole forms, and a shockwave ripples outward creating the supernova.

It turns out that the density and energy of the shockwave on its own isn’t enough to actually generate the supernova, and overcome the gravitational force pulling it inward. Instead, it’s believed that neutrinos created at the core pile up behind the shockwave, and give it the push it needs to blast outward into space.

In some cases, though, it’s believed that this additional energy doesn’t show up. Instead of rebounding from the core of the star, the black hole just gobbles it all up. In a fraction of a second, the star is just… gone.

According to astronomers, it might be the case that 1/3rd of all core collapse supernovae die this way, which means that a third of the supergiant stars are just disappearing from the sky. They’re there, and then a moment later, they’re not there.

Artist's rendering of a black hole. Image Credit: NASA

And this is all that remains. Image Credit: NASA

Seriously, imagine the forces and energy it must take to swallow an entire red supergiant star whole. Black holes are scary.

Astronomers have gone looking for these things, and they’ve actually been pretty tricky to find. It’s like one of those puzzles where you try to figure out what’s missing from a picture. They studied images of galaxies taken by the Hubble Space Telescope, looking for bright supergiant stars which disappeared. In one survey, studying a large group of galaxies, they only turned up a single candidate.

But they only surveyed a handful of galaxies. To really get serious about searching for them, they’ll need better tools, like the Large Synoptic Survey Telescope due for first light in just a few years. This amazing instrument will survey the entire sky every few nights, searching for anything that changes. It’ll find asteroids, comets, variable stars, supernovae, and now, supergiant stars that just disappeared.

We’ve talked about failed supernovae. Now let’s take a few moments and talk about the complete opposite: super successful supernovae.

When a star with more than 8 times the mass of the Sun explodes as a supernova, it leaves behind a remnant. For the lower mass star explosions, they leave behind a neutron star. If it’s a higher mass star, they leave behind a black hole.

But for the largest explosions, where the star had more than 130 times the mass of the Sun, the supernova is so powerful, so complete, there’s no remnant behind. There’s an enormous explosion, and the star is just gone.

No black hole ever forms.

Artist's impression of a Type II supernova explosion which involves the destruction of a massive supergiant star. Credit: ESO

Artist’s impression of a supernova explosion which involves the destruction of a massive supergiant star. Credit: ESO

Astronomers call them pair instability supernovae. In a regular core collapse supernova, the layers of the star collapse inward, producing the highly dense remnant. But in these monster stars, the core is pumping out such energetic gamma radiation that it generates antimatter in the core. The star explodes so quickly, with so much energy, it totally overpowers the gravity pulling it inward.

In a moment, the star is completely and utterly gone, just expanding waves of energy and particles.

Only a few of these supernovae have ever been observed, and they might explain some hypernovae and gamma ray bursts, the most powerful explosions in the Universe.

Beyond 250 times the mass of the Sun, however, gravity takes over again, and you get enormous black holes.

As always, the Universe behaves more strangely than we ever thought possible. Some supernova fail, completely imploding as a black hole. And others detonate entirely, leaving no remnant behind. Trust the Universe to keep mixing it up on us.

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3 Responses

  1. Nikola Milovic says:

    All these reflection and discussion of supernova stars and black holes, generally do not agree with the true phenomena in the universe, for whom science does not possess any knowledge of his organization.
    In the universe there is order of appearance and disappearance of matter, which is repeated at certain intervals. When the matter is formed from the ether that fills the endless universe, occurs the quark gluon plasma with enormously high magnetism, temperature, and attractive forces. In a thermodynamic process of change, forming the said plasma, which are formed from electrons, protons later, and these electrons are drawn into protons forming a neutron star, which is due to internal tensions explode as a supernova. Then form atoms, molecules, clouds of various atoms and molecules, which leads to the formation of stable celestial bodies such as stars and their accompanying planets. In the formation of matter is formed and gravity, which gathers the matter later in piles mass (of the heavenly bodies to clusters of galaxies) and it is held until they are in some places formed the critical mass and critical gravity, when the matter is transformed back into form of ether, from which it is derived substances. These places are black holes, from back in the material and energy entities of the universe (SEU) can not come back, but only back in the form of ether. This is a brief description of the structure of the universe, but not in the way you imagine it.

    • BCstargazer says:

      i sure would like to read your peer reviewed paper that explains the observed and repeatable processes that leads to the “appearance and disappearance” of matter because i want to apply it to my apparition to your acceptance ceremony of your Nobel prize in Oslo …

  2. Jim Krug says:

    This was a really good article! Even being an astronomy teacher, the process described here between supernova/black hole/neutron star/pulsar can be very nebulous.

    I like how this article differentiated between what happens vs. the mass of the star itself. Very helpful!

    Here is my only question: I have read that if a neutron star survives the initial supernova, that the NEUTRON STAR is what actually implodes again, forming the black hole. Is that not correct at all, or is that still correct in some mass scenarios? Thanks.

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