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 Unraveling the nature of 'whistlers' from space in the lab
15.08.2018 | American Institute of Physics

nachricht Early opaque universe linked to galaxy scarcity
15.08.2018 | University of California - Riverside

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: Unraveling the nature of 'whistlers' from space in the lab

A new study sheds light on how ultralow frequency radio waves and plasmas interact

Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

Im Focus: The “TRiC” to folding actin

Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.

Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...

Im Focus: Lining up surprising behaviors of superconductor with one of the world's strongest magnets

Scientists have discovered that the electrical resistance of a copper-oxide compound depends on the magnetic field in a very unusual way -- a finding that could help direct the search for materials that can perfectly conduct electricity at room temperatur

What happens when really powerful magnets--capable of producing magnetic fields nearly two million times stronger than Earth's--are applied to materials that...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

2018 Work Research Conference

25.07.2018 | Event News

 
Latest News

Staying in Shape

16.08.2018 | Life Sciences

Diving robots find Antarctic seas exhale surprising amounts of carbon dioxide in winter

16.08.2018 | Earth Sciences

Protein droplets keep neurons at the ready and immune system in balance

16.08.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>