May 7 (UPI) — When the sun finally dies, 10 billion years from now, it will become a planetary nebula, according to a team of scientists at the University of Manchester.
Some 90 percent of all stars become planetary nebulae during their afterlife, but some astronomers questioned whether the sun had sufficient mass to follow the traditional path.
Manchester researchers built a new stellar model to predict the luminosity of the envelope of gas and dust ejected by stars of different masses.
“When a star dies it ejects a mass of gas and dust — known as its envelope — into space, Manchester astronomer Albert Zijlstra said in a news release. “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.”
Whether or not an ejected envelope glows brightly in space revealing its presence depends on the size and strength of remaining core. Sometime, a core will continue to pump out radiation for another 10,000 years, causing the surrounding as and dust to shine brightly.
“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,” Zijlstra said.
Until now, observational data from planetary nebulae conflicted with cosmic modeling. Data collected by ground and space telescopes suggested all the brightest nebulae were equally bright, regardless of the galaxies they were found in.
“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,” Zijlstra said. “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 models that showed after the envelope of gas and dust is ejected, the remaining stellar core glows as much as three times brighter than expected, allowing relatively low-mass stars like the sun to form glowing planetary nebulae.
“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,” Zijlstra said. “Problem solved, after 25 years!”
Researchers published their breakthrough in the journal Nature Astronomy.