Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists model physics of stellar burning

15.04.2005


University of California scientist at Los Alamos National Laboratory working with astronomers from around the world recently validated a computer model that predicts the rebirth and stellar burning and mixing processes of evolved stars. The discovery is a leap forward in our understanding of how stars like the sun evolve through violent outbursts during their evolution.



In research published recently in the journal Science, Laboratory astrophysicist Falk Herwig and his colleagues describe how Herwig’s computer model was recently corroborated by radio telescope observations made at the Very Large Array (VLA) in Socorro, N.M. The radio signals collected by the VLA indicate that a star in the constellation Sagittarius known as V4334 Sgr, or Sakurai’s Object, is about to re-illuminate it’s planetary nebula for the second time, initiating a new phase in the spectacular evolution of this enigmatic star. This never before seen event is another step in a complex chain of events initially triggered by a nuclear burst after the star had already become a hot white dwarf.

Computer simulations of the stellar outburst made nearly 10 years ago by Herwig and others had predicted this series of physics events that would lead up to the rejuvenated planetary nebula. However, V4334 Sgr failed to follow the script as events moved many times more quickly than the simulations predicted. In 2001, Herwig proposed a new fast-evolving model, claiming the problem may be the way in which nuclear burning and rapid mixing was simulated.


Stars typically evolve into white dwarfs and die when they have used up most of their hydrogen, but about a quarter of them, like V4334 Sgr, experience a brief rebirth when their helium suddenly ignites, and the remaining hydrogen in the outer regions is drawn into the helium shell through rapid mixing, causing a massive nuclear explosion. This burst of energy will expand the dying star to gigantic proportions and lower surface temperatures and, in the process, expel prodigious amounts of carbon. V4334 Sgr has just evolved through this phase.

Herwig’s new model predicts that V4334 Sgr will now become much hotter very rapidly and will then slowly repeat the stellar rebirth cycle once more, returning to its current cooler temperature in roughly two hundred years. Only then follows the final episode of reheating for a third time before V4334 Sgr eventually will become an inactive cooling white dwarf.

In addition to Herwig, who works in the Laboratory’s Theoretical Division, the stellar burning team included Marcin Hajduk of the University of Manchester and Centrum Astronomii UMK; Peter A.M. van Hoof of Queen’s University in Belfast and the Royal Observatory of Belgium; Florian Kerber of the European Southern Observatory in Germany; Stefan Kimeswenger of the University of Innsbruck, Austria; Don Pollacco of Queen’s University in Belfast; Aneurin Evans of Keele University in Staffordshire, UK; Jose Lopez of the National Autonomous University of Mexico in Ensenada; Myfanwy Bryce of Jodrell Bank Observatory in the UK; Stewart P.S. Eyres of the University of Central Lancashire in the UK; and Albert Zijlstra and Mikako Matsuura of the University of Manchester.

Los Alamos National Laboratory is operated by the University of California for the National Nuclear Security Administration of the U.S. Department of Energy and works in partnership with NNSA’s Sandia and Lawrence Livermore national laboratories to support NNSA in its mission.

Los Alamos enhances global security by ensuring the safety and reliability of the U.S. nuclear deterrent, developing technologies to reduce threats from weapons of mass destruction, and solving problems related to defense, energy, environment, infrastructure, health and national security concerns.

Todd Hanson | EurekAlert!
Further information:
http://www.lanl.gov

More articles from Physics and Astronomy:

nachricht Unconventional superconductor may be used to create quantum computers of the future
19.02.2018 | Chalmers University of Technology

nachricht Hubble sees Neptune's mysterious shrinking storm
16.02.2018 | NASA/Goddard Space Flight Center

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

Im Focus: Hybrid optics bring color imaging using ultrathin metalenses into focus

For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.

But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...

Im Focus: Stem cell divisions in the adult brain seen for the first time

Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.

The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...

Im Focus: Interference as a new method for cooling quantum devices

Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters

Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Contacting the molecular world through graphene nanoribbons

19.02.2018 | Materials Sciences

When Proteins Shake Hands

19.02.2018 | Materials Sciences

Cells communicate in a dynamic code

19.02.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>