While scientists widely agree that the sun will die in approximately 10 billion years, until now what would happen to it remained unclear.

Now, researchers from the University of Manchester predict that it will turn into a massive ring of luminous, interstellar gas and dust, known as a planetary nebula.

The team developed a new model that predicts the lifecycle of stars.

Professor Albert Zijlstra, who led the study, said: “When a star dies it ejects a mass of gas and dust – known as its envelope – into space.

“The envelope can be as much as half the star’s mass. This reveals the star’s core, which by this point in the star’s life is running out of fuel, eventually turning off and before finally dying.

"It is only then the hot core makes the ejected envelope shine brightly for around 10,000 years – a brief period in astronomy.

“This is what makes the planetary nebula visible. Some are so bright that they can be seen from extremely large distances measuring tens of millions of light years, where the star itself would have been much too faint to see."

The model also solves another problem that has baffled astronomers for a quarter of a century.

Around 25 years ago astronomers discovered that if you look at planetary nebulae in another galaxy, the brightest ones always have the same brightness – regardless of their age.

Professor Zijlstra said: “Old, low mass stars should make much fainter planetary nebulae than young, more massive stars. This has become a source of conflict for the past for 25 years.

"The data said you could get bright planetary nebulae from low mass stars like the sun, the models said that was not possible, anything less than about twice the mass of the sun would give a planetary nebula too faint to see.”

The new model revealed that after the ejection of the envelope, the stars heat up three times faster than found in older models, making it easier for a low mass star, such as the sun, to form a bright planetary nebula.

Professor Zijlstra added: "We found that stars with mass less than 1.1 times the mass of the sun produce fainter nebula, and stars more massive than 3 solar masses brighter nebulae, but for the rest the predicted brightness is very close to what had been observed. Problem solved, after 25 years!”

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