Scientists agree the sun will die in approximately five billion years, but they weren’t sure what would happen next…until now.

A team of international astronomers, including Professor Albert Zijlstra from the School of Physics & Astronomy, predict it will turn into a massive ring of luminous, interstellar gas and dust, known as a planetary nebula.

A planetary nebula marks the end of 90% of all stars active lives and traces the star’s transition from a red giant to a degenerate white dwarf. But, for years, scientists weren’t sure if the sun in our galaxy would follow the same fate: it was thought to have too low mass to create a visible planetary nebula.

To find out the team developed a new stellar, data-model that predicts the lifecycle of stars. The model was used to predict the brightness (or luminosity) of the ejected envelope, for stars of different masses and ages. The research is being published in Nature Astronomy.

Prof Zijlstra explains: “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 been perplexing astronomers for a quarter of a century.