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Using A Stellar Ultrasound To Determine Ages Of Young Stars

July 4, 2014
Image Caption: A composite image detailing the pre-life story of a star like the Sun, spanning about 10 million years from conception to birth. Credits: Pieter Degroote (KU Leuven) / background image: ESO

Brett Smith for redOrbit.com – Your Universe Online

Before they become full-fledged stars, young embryonic stars are essentially contracting molecular clouds of gas and dust particles. The age of these ‘baby stars’ is difficult to gauge, but a newly published study in the journal Science has revealed scientists used a technique similar to ultrasound technology to determine the age of these young stars.

“Think of it as ultrasound of stellar embryos,” explained study author Jaymie Matthews, an astronomer at University of British Columbia.

As a star grows from baby to ‘teenager,’ gravitational draw causes it to shrink, becoming smaller and hotter until the central temperature is enough to start the nuclear incineration of hydrogen. At this point, the star has become an ‘adult’.

In the new study, the astrophysicists use measurements of acoustic vibrations to determine how far along a star is in the development process. The team used data from Canadian Space Agency’s MOST satellite and the French CoRoT mission.

“Stars can vibrate due to sound waves bouncing inside,” Matthews said. “We detect the sound vibrations across the vacuum of space by the subtle changes in stellar brightness. Then we translate the frequencies of those vibrations into models of the structures of those stars’ hidden interiors.”

“Our data shows that the youngest stars vibrate slower while the stars nearer to adulthood vibrate faster,” study author Konstanze Zwintz, a postdoctoral researcher at the University of Leuven’s Institute for Astronomy in Belgium. “A star’s mass has a major impact on its development: stars with a smaller mass evolve slower. Heavy stars grow faster and age more quickly.”

The new study confirms earlier theories which said young stars pulsate differently than older stars.

“We now have a model that more precisely measures the age of young stars,” Zwintz said. “And we are now also able to subdivide young stars according to their various life phases.”

Another study published in May found the prevailing theory surrounding star formation may have to be rethought. That study said some of the oldest stars in known clusters sit on the exterior of their groups, not the interior where the densest concentrations of stellar material sit.

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Source: Brett Smith for redOrbit.com - Your Universe Online



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