'Born-again' stars reveal how the earth was created

Apr 07, 2005

Scientists at The University of Manchester have unveiled new research which shows how exploding stars may have helped to create the earth. The discovery was made during a unique research project examining how some dead stars re-ignite and come back to life.
Professor Albert Zijlstra's study of Sakurai's Object - the only star which has been observed re-igniting in modern times - has led him to conclude that 5% of the carbon on earth may have been come from stardust expelled by stars exploding back to life.

"Up to 0.1% of the total mass of the star, which is equivalent to 300 times the mass of the earth, can be expelled when a star re-ignites," says Professor Zijlstra.

"This discovery not only gives us a new understanding of where the natural material that made up the earth came from, but also leads us to believe that part of the carbon in the universe could have come from these events."

Stars die when they have used up most of their hydrogen. For the Sun, this will happen in about 4.5 billion years. But some stars will experience a brief rebirth when their helium suddenly ignites, and the remaining hydrogen in their outer envelope is drawn into the helium shell. After the explosive re-ignition, the star will expand to giant proportions - expelling tonnes of carbon in the process - before rapidly burning out again.

"We expect that some 25% of all stars will experience such a re-ignition, but this is an extremely rare occurrence, and we will probably only see it happen once every hundred years or so", says Professor Zijlstra.

Incredibly, the earth's formation was not the main focus of Professor Zijlstra's research, which sought to establish a better understanding of why Sakurai's Object had re-ignited.

Computer simulations had predicted a series of events that would follow such a re-ignition, but the star didn't follow the script - events moved 100 times more quickly than the simulations predicted.

"Sakurai's Object went through the first phases of this sequence in just a few years - 100 times faster than we expected - so we had to revise our models. We've now produced a new theoretical model of how this process works, and the observations have provided the first evidence supporting our new model," Zijlstra said.

"It's important to understand this process. Sakurai's Object has ejected a large amount of carbon into space, both in the form of gas and dust grains. These will find their way into regions of space where new stars form, and the dust grains may become incorporated in new planets. Our results suggest this source for cosmic carbon may be far more important than previously suspected," Zijlstra added.

Zijlstra's findings will be presented in the April 8 issue of the prestigious journal Science.

Source: University of Manchester

Explore further: Manchester scientists boost NASA's missions to Mars

add to favorites email to friend print save as pdf

Related Stories

What is the difference between asteroids and comets?

Nov 20, 2014

Asteroids and comets have a few things in common. They are both celestial bodies orbiting our Sun, and they both can have unusual orbits, sometimes straying close to Earth or the other planets. They are both ...

Recommended for you

ESA image: The gold standard

1 hour ago

The Eutelsat-9B satellite with its EDRS-A payload is shown in the anechoic test chamber of Airbus Defence and Space in Toulouse, France, having completed its final antenna pattern tests today.

Frost-covered chaos on Mars

1 hour ago

Thanks to a break in the dusty 'weather' over the giant Hellas Basin at the beginning of this year, ESA's Mars Express was able to look down into the seven kilometre-deep basin and onto the frosty surface ...

Rosetta's comet: In the shadow of the coma

8 hours ago

This NAVCAM mosaic comprises four individual images taken on 20 November from a distance of 30.8 km from the centre of Comet 67P/C-G. The image resolution is 2.6 m/pixel, so each original 1024 x 1024 pixel ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.