Wouldn’t it be great to know that a giant star is about to die in a cataclysmic supernova explosion? A team of astronomers did just that. If you see a red giant star surrounded by a thick layer of material, be careful – the star will likely explode within a few years.
As a massive star approaches the end of its life, it goes through several violent phases. Deep in the star’s core, it changes from combining hydrogen, starting with helium, to combining heavier elements and combining carbon, oxygen, magnesium, and silicon. A star forms iron in its core at the end of the chain. This spells the end of the star, as the iron dissipates the energy instead of releasing it, and in less than ten minutes, it transforms in an explosion of its own. supernova.
But despite all the commotion going on in the stars’ hearts, it’s hard to tell exactly what’s going on from the outside. Of course, near the end of their lives, these giant stars swell to extreme sizes. They are also intensely bright – tens of thousands of times brighter they are. Because the surfaces of stars are so tilted, their outer temperatures actually drop, making them, as it were, cool network giants.
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It is the most famous example of such a star near a terminal Betelgeuse. If it were placed inside us solar systemThis star, which is only 11 times larger than the Sun, will reach the orbit of the planet. Jupiter. It will go supernova any day now, but to an astronomer, “any day” could be a million years away. Although we know that such stars will eventually explode in a supernova, no more precise estimate can be obtained. Or, at least, it used to be.
Time bomb
Now a team of astronomers has developed a method to detect supernovae that will die out within a few years. They reported their results in a paper Published in the arXiv preprint database and accepted for publication in Monthly Notices of the Royal Astronomical Society.
They studied several dozen unique supernovae, specifically known as Type II-P supernovae. Unlike other supernovae, these explosions remain bright long after the initial explosion.
In several instances, astronomers have looked through old catalogs and found images of stars before they exploded, all of which appear to be red supergiants like Betelgeuse. This is a clear indication that such stars are supernova candidates and are ready to go out at a moment’s notice.
Stars that result in such supernovae are thought to have dense mantles of material surrounding them before exploding. These shrouds are much denser than those measured around Betelgeuse. It is the heating of that material from the initial shock wave that causes the glow to lengthen; There’s simply more stuff around for a good glow after the first sign of a breakout.
This dense shroud also causes this type of supernova to appear more quickly than its more open cousins. When the explosion initially occurs, the shock wave hits the material around the star, causing the shock wave to lose steam as it passes through. Although the energies of the supernova are initially sufficient to release high-energy radiation such as X-rays and gamma rays, after the shock wave mixes with the surrounding material, the radiation emitted is at optical wavelengths.
It seems that this dense material shrouds around stars it is also a gift that a supernova will occur.
super cocoons
But how long does it take to create a shroud of this material? The researchers studied two models. In one model, high-velocity winds blew from the star’s surface, which slowly separated its parts and spread them around to form a shroud over decades. In the second model, the star underwent a violent explosion before the supernova, which sent 1/10 the mass of gas. the mass of the sun it goes into orbit in less than a year.
The researchers then modeled how all this material would affect our images of the star. In either case, once the star has established its shroud, it will be too dim to detect with our current imaging technology.
Because we have direct images of some pre-supernova stars taken 10 years before they went out, astronomers concluded that the slow-and-steady model wouldn’t work. Otherwise, the star would be obscured.
All of this means that a supergiant star will go supernova within a few years after being enveloped by a thick layer of material around itself. So, if you’re traveling through space and encounter this exact scenario, consider yourself warned.
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