. 24/7 Space News .
Scientists Crack Open Stellar Evolution

Plumes of carbon in low mass stars are shown being lifted (red) by rising hydrogen-rich clouds (green).
by Staff Writers
Livermore CA (SPX) Oct 30, 2006
Using 3D models run on some of the fastest computers in the world, Laboratory physicists have created a mathematical code that cracks a mystery surrounding stellar evolution. For years, physicists have theorized that low-mass stars (about one to two times the size of our sun) produce great amounts of helium 3 when they exhaust the hydrogen in their cores to become red giants, most of their makeup is ejected, substantially enriching the universe in this light isotope of helium.

This enrichment conflicts with the Big Bang predictions. Scientists theorized that stars destroy this helium 3 by assuming that nearly all stars were rapidly rotating, but even this failed to bring the evolution results into agreement with the Big Bang.

Now, by modeling a red giant with a fully 3D hydrodynamic code, LLNL researchers identified the mechanism of how and where low-mass stars destroy the helium 3 that they produce during evolution.

They found that helium 3 burning in a region just outside of the helium core, previously thought to be stable, creates conditions that drive this newly discovered mixing mechanism.

Bubbles of material, slightly enriched in hydrogen and substantially depleted in helium 3, float to the surface of the star and are replaced by helium 3-rich material for additional burning. In this way the stars destroy their excess helium 3, without assuming any additional conditions (like rapid rotation).

"This confirms how elements evolved in the universe and makes it consistent with the Big Bang," said David Dearborn, a Lawrence Livermore National Laboratory physicist. "The previous one-dimensional model did not recognize the instability created by burning helium 3."

The same process applies to low-mass metal poor suns, which may have been more important than metal-rich stars like the sun throughout the earlier part of galactic history in determining the helium 3 abundance of the interstellar medium.

The research appears in the Oct. 26 edition of Science Express.

The Big Bang is the scientific theory of how the universe emerged from a tremendously dense and hot state about 13.7 billion years ago.

The Big Bang produced about 10 percent 4He, .001 percent helium 3 with almost the rest made up of hydrogen.

Later, low mass stars should have increased that helium 3 production to .01 percent. However, observations of helium 3 in the interstellar medium show that it remains at .001 percent. So where did that helium 3 go?

That's where the Livermore team comes in. Livermore scientists Peter Eggleton and Dearborn collaborated with John Lattanzio of the Centre for Stellar and Planetary Astrophysics in Australia to create a code that describes how helium 3 burns during star formation so that the makeup of the universe after the Big Bang is reconciled.

"Prior to our work, it was perceived that the helium 3 in the envelope was largely indestructible, and would be blown off later into space, thus enriching the interstellar medium and causing the conflict with the Big Bang," said Eggleton, an astrophysicist and lead author of the paper. "What we find is that helium 3 is unexpectedly destructible, by a mixing process driven by a phenomenon that has been ignored so far."

Related Links
Stellar Chemistry, The Universe And All Within It



Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News


NASA Gives WISE Decision The Go Ahead
Pasadena (UPI) Oct 30, 2006
NASA has approved construction of a satellite that will scan the entire sky in infrared light to detect cool stars and bright galaxies.







  • The Spark Of A New Era
  • ISRO Moots Manned Mission To Space
  • Space Radiation Threats To Astronauts Addressed In Federal Research Study
  • NASA, Lock-Mart, Boeing to Speak at Phoenix Integration System of Systems Workshop

  • The Search For Martian Water Is In The Fine Details
  • Martian Poles In The Swiss Alps
  • 1000 Sols On Mars
  • Preparations Continue For Manned Expedition To Mars One Day

  • ATK Receives $17.5 Million Contract For CASTOR 120-R Motors
  • Russian Space Co. To Launch At Least 11 Satellites By 2009
  • MetOp Weather Satellite Reaches Polar Orbit
  • European Weather Satellite Pencilled For New Launch Bid

  • A Growing Intelligence Around Earth
  • Start of Operations Phase For ALOS And Data Provision To The Public
  • Afghanistan Opium Cultivation Monitored By International DMC Constellation
  • Deimos And Surrey Satellite Technology Contract For Spanish Imaging Mission

  • Scientist Who Found Tenth Planet Discusses The Downgrading Of Pluto
  • New Horizons Spacecraft Snaps Approach Image of the Giant Planet
  • Does The Atmosphere Of Pluto Go Through The Fast-Freeze
  • Surprises From The Edge Of The Solar System

  • Scientists Crack Open Stellar Evolution
  • Snake On A Galactic Plane
  • NASA Gives WISE Decision The Go Ahead
  • Astronomers Weigh 200-Million-Year-Old Baby Galaxies

  • New Russian Spaceship Will Be Able To Fly To Moon - Space Corp
  • Ice Store At Moon's South Pole Is A Myth
  • No Lunar Polar Ice Sheets Found In High Resolution Radar Images
  • In Space Everyone Can Hear You Misspeak

  • Second Modernized GPS Satellite Built By LockMart Begins Service
  • India May Quit EU-led GPS project
  • EU Refuses To Rule Out Military Role For Galileo GPS Network
  • Boeing Delivers Hardware And Completes Software Testing For GPS

  • The content herein, unless otherwise known to be public domain, are Copyright 1995-2006 - SpaceDaily.AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA PortalReports are copyright European Space Agency. All NASA sourced material is public domain. Additionalcopyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by SpaceDaily on any Web page published or hosted by SpaceDaily. Privacy Statement