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An international team of astrophysicists has learned to determine how soon a supernova will explode. Tell us more about their discovery
What’s going on
- A supernova or supernova explosion is the process of star death, in which it sharply increases its brightness by several orders of magnitude, and then slowly fades, releasing a large amount of energy.
- A team of astrophysicists studied pre-explosion catalogs of Type II-P stars — the ones that stay brightest longest after the outburst — and found a pattern. All the stars, surrounded by a dense veil of matter, exploded within a few years. Using computer simulations, they determined that matter forms over several years (which is very fast), heats up and makes a supernova brighter.
- After the explosion, the shock wave collides with matter around the star and loses energy.
- The researchers suggested two scenarios for the appearance of the shell. According to the first, high-speed winds blew particles from the surface of the star, and they gradually enveloped the supernova over decades.
- In the second case, the star survived another explosion before the supernova explosion, which released gas into orbit with a mass of up to 1/10 of the Sun – and this happened within just one year.
What does it mean
All chemical elements in the universe appeared as a result of the explosion of supernova stars. Scientists distinguish two types of explosions: core collapse and thermonuclear explosion. As a result of the collapse of the core, stars with a mass several times greater than the Sun explode – these include type II-P supernovae. They can be compared to an onion: on top there is a shell of light hydrogen nuclei, followed by carbon and oxygen, and in the core there is gas heated to billions of degrees and compressed gas from iron nuclei.
When a star “runs out” of the shell fuel, due to strong gravity in the center of the core, its collapse occurs, accompanied by a powerful shock wave. It carries with it particles of matter from the upper layers – it is the gas that gives the light flash that scientists observe. What remains at the site of the explosion is a neutron star the size of the Sun – or a black hole.
A supernova explosion is a rather rare phenomenon, often impossible to detect due to dense gas and dust clouds that absorb light. It was supernovae that allowed scientists to discover dark energy and establish the expansion of the Universe. And the formation of black holes allows us to study gravity.
One of the most famous contenders for supernova status is a star in the constellation of Orion, Betelgeuse. It is 1 thousand times larger than the Sun and is comparable in size to the solar system. Betelgeuse is already more than 10 million years old, it is at the last stage of evolution and, according to scientists, it will explode as a supernova very soon – in 1,5 million years.