Sun set to finish its life as a planetary nebula
A dramatic death is predicted for the sun in 10 billion years time as our parent star morphs into a planetary nebula, say UK scientists.
Until now astronomers have agreed on the sun’s expected life span, but the nature of its death has been controversial.
The new research suggests that the sun will transform into a planetary nebula – a massive glowing globe of gas and dust.
Planetary nebulae are among the most beautiful and striking objects seen by astronomers, some shining bright enough to be seen across distances of millions of light years.
But a star has to be above a certain mass to create a visible nebula. Until now it was thought the sun was too light.
The new research published in the journal Nature Astronomy shows that the sun is just massive enough to end its life in glorious style, as a luminous planetary nebula.
Professor Albert Zijlstra, a member of the international team from the University of Manchester, 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 scientists developed a new data model to that predicts the life cycle of stars.
It showed that after ejection of the envelope, dying stars heated up three times faster than was previously thought. This made it much easier for a low-mass star such as the sun to produce a bright planetary nebula.