Parent star’s long ‘napping’ could trigger the formation of baby stars

March 10th, 2011 - 5:34 pm ICT by ANI  

Washington, Mar 10 (ANI): It has long been suspected that the build up of material onto young stars is not continuous but happens in episodic events, resulting in short outbursts of energy from these stars.

However, this has been largely ignored in models of star formation.

Now, Cardiff University astrophysicists Dimitris Stamatellos and Anthony Whitworth, along with David Hubber from the University of Sheffield, have developed advanced computer models to gain a rare insight into the formation of stars.

They believe that a young star’s long ‘napping’ could trigger the formation of a second generation of smaller stars and planets orbiting around it.

While stars are young they are surrounded by discs of gas and dust, and grow by accreting material from these discs. The discs may break-up to give birth to smaller stars, planets and brown dwarfs.

“We know that young stars spend most of their early lives sleeping,” said Stamatellos.

“After they have their lunch - a large chunk of dust and gas from their discs - they take a nap that lasts for a few thousand years. During this nap their brightness is very low,” he said.

“As they sleep, their discs grow in mass, but they remain relatively cool, despite the presence of stars right at their centres. Eventually, these discs become unstable and fragment to form low-mass stars and substellar objects, like brown dwarfs and planets,” he added.

To date, research has suggested that the radiation from the parent star could heat and stabilize the disc, suppressing its breaking up.

However, the researchers discovered that there is ample time in between outbursts to allow the disc to break up and give birth to a new generation of low-mass stars, brown dwarfs, and planets.

The new theory provides an explanation for the formation and the properties of stars with masses below a fifth of that of our Sun, which are estimated to constitute more than 60 percent of all stars in our Galaxy.

“Our findings suggest that disc fragmentation is possible in nature,” said Stamatellos.

“It is important now to investigate whether this is the dominant mechanism for the formation of low-mass stars and brown dwarfs,” he added.

The research is published in the Astrophysical Journal. (ANI)

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