Putting the energy of pounds or tons of explosive into something as light and thin as a sheet of paper (the shock), means it has to be moving very fast. In the case of high explosives, something like 40% of the energy ends up in the shock. In the case of a white dwarf, if the carbon burning does transition to a detonation, that means that the combustion front becomes as thin as the shock and the reaction energy is liberated as the shock passes through it, and the energy of the reaction gets added to the shock (and also used to heat the shocked media). Shocks aways propagate faster than the speed of sound in the unshocked media (and at the speed of sound in the shocked media). The reason shocks are so destructive is because they are discontinuous, the material doesn't have time to deform and spread the load before the shock disrupts it. In something with a very short mean-free-path it is even thinner. To those who don't appreciate what that means, a "shock" is a discontinuous propagating wave. What makes a supernova "super" is that much of the energy is tied up in the shock wave.
I think you would need essentially a triggered implosion, where the initiation was triggered simultaneously at multiple points on the surface to trigger imploding shock waves. Neutron stars have densities ~10^9 higher than a white dwarf and it takes a much higher density to reach a black hole. But that would be unlikely because it would require pretty much simultaneously initiation of deflagration on opposite sides of the white dwarf so the shock waves intersected and produced net compression of macroscopic quantities such that the gravity of that compressed region would be enough to maintain the high density. If the deflagration wave of carbon burning in a white dwarf does turn into a shock, then it is conceivable that there could be regions of high density produced that did form black holes. If white dwarfs don't collapse into neutron stars, that is only because they are too hot, there is too much thermal energy for the mass to remain unbound. If neutron stars are stable against the formation of a black hole, then certainly white dwarfs should be. Neutron stars have a higher mass and a much lower radius. But there is a much faster way that's also extremely common in our Universe: start with a short-lived, hot, blue, massive star! The most massive of these stars can burn through their fuel over 100,000 times as fast as our Sun does, first fusing hydrogen into helium, then helium into carbon, and so on, in layers, until it begins building up iron, which can no longer be fused, in its core.Įthan, the density of a white dwarf is much less than that of a neutron star. That's one way - the slow way - to make a supernova. The atoms at the core of this white dwarf fail to support the star under the tremendous stress of gravity! The white dwarf star is completely destroyed, as the interior collapses down to form a black hole, where nothing can escape! The process of collapse, even though it lasts just a few seconds, results in a tremendous release of energy into the outer layers.Īnd the outer layers heat up tremendously, expand incredibly rapidly and get strewn across space for light years! This is what a supernova is in particular, a type I supernova, the same type as the one you can see in the Pinwheel Galaxy, and the same type that occurred in the famed 1572 supernova. Images retrieved from PLASMA Team Snc and Charles Horowitz. When a white dwarf star lives in a binary star system with a relatively close companion star, it can begin to gravitationally siphon off some of the mass of the larger, less dense companion!
But, much as is the case for Sirius, a substantial portion of stars exist in binary or even trinary star systems.
Now, in our Solar System, there is but one star. Made out of the condensed atoms packed closely together under the tremendous force of gravity, but without any nuclear fusion at the core, white dwarf stars, although they can easily be as massive as our Sun, are only physically about the size of Earth, making them around 300,000 times as dense as our planet. However, they're both about 10,000 times less bright and a factor of a million lower in volume than the stars they came from. White dwarfs can be the same color, temperature, and nearly the same mass (up to about 70%) of the bright stars that gave rise to them.
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