Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Astronomers Witness Biggest Star Explosion, Massive Supernova

07.12.2009
What happens when a really gargantuan star – one hundreds of times bigger than our sun – blows up?

Although a theory developed years ago describes what the explosion of such an enormous star should look like, no one had actually observed one – until now.

An international team, led by scientists in Israel and including researchers from Germany, the US, the UK, and China, tracked a supernova – an exploding star – for over a year and a half, and found that it neatly fits the predictions for the explosion of a star greater than 150 times the sun’s mass. Their findings, which could influence our understanding of everything from natural limits on star size to the evolution of the universe, appeared recently in Nature.

“It’s all about balance,” says team leader Dr. Avishay Gal-Yam of the Weizmann Institute of Science’s Department of Particle Physics and Astrophysics. “During a star’s lifetime, there’s a balance between the gravity that pulls its material inward and the heat produced in the nuclear reaction at its core, pushing it out. In a supernova we’re familiar with, of a star 10 to 100 times the size of the sun, the nuclear reaction begins with the fusion of hydrogen into helium, as in our sun. But the fusion keeps going, producing heavier and heavier elements, until the core turns to iron. Since iron doesn’t fuse easily, the reaction burns out, and the balance is lost. Gravity takes over and the star collapses inward, throwing off its outer layers in the ensuing shockwaves.”

The balance in a super-giant star is different. Here, the photons (light particles) are so hot and energetic, they interact to produce pairs of particles: electrons and their opposites, positrons. In the process, particles with mass are created from the massless photons, and this consumes the star’s energy. Again, things are thrown out of balance, but this time, when the star collapses, it falls in on a core of volatile oxygen, rather than iron. The hot, compressed oxygen explodes in a runaway thermonuclear reaction that obliterates the star’s core, leaving behind little but glowing stardust. “Models of ‘pair supernovae’ had been calculated decades ago,” says Dr. Gal-Yam, “but no one was sure these huge explosions really occur in nature. The new supernova we discovered fits these models very well.”

An analysis of the new supernova data led the scientists to estimate the star’s size at around 200 times the mass of the sun. This in itself is unusual, as observers had noted that the stars in our part of the universe seem to have a size limit of about 150 suns; some had even wondered if there was a physical constraint on a star’s girth. The new findings suggest that hyper-giant stars, while rare, do exist, and that even larger stars, up to 1,000 times the size of the sun, may have existed in the early universe. “This is the first time we’ve been able to analyze observations of such a massive exploding star,” says Dr. Paolo Mazzali of the Max Planck Institute for Astrophysics in Germany, who led the theoretical study of this object. “We were able to measure the amounts of new elements created in this explosion, including approximately five times the mass of our sun in highly radioactive, freshly synthesized nickel. Such explosions may be important factories for heavy metals in the universe.”

This massive supernova was found in a tiny galaxy only a hundredth the size of our own, and the scientists think that such dwarf galaxies could be natural harbors for the giant stars, somehow enabling them to surpass the 150-sun limit.

“Our discovery and analysis of this unique explosion has given us new insights into just how massive stars can get and how these stellar giants contribute to the makeup of our universe,” says Dr. Gal-Yam. “We hope to understand even more when we find additional examples from new surveys that we have recently begun to carry out, covering large, previously unexplored areas of the universe.”

Dr. Avishay Gal-Yam’s research is supported by the Nella and Leon Benoziyo Center for Astrophysics; the Peter and Patricia Gruber Awards; the William Z. & Eda Bess Novick New Scientists Fund; the Legacy Heritage Fund Program of the Israel Science Foundation; and Miel de Botton Aynsley, UK.

The Weizmann Institute of Science in Rehovot, Israel, is one of the world's top-ranking multidisciplinary research institutions. Noted for its wide-ranging exploration of the natural and exact sciences, the Institute is home to 2,600 scientists, students, technicians and supporting staff. Institute research efforts include the search for new ways of fighting disease and hunger, examining leading questions in mathematics and computer science, probing the physics of matter and the universe, creating novel materials and developing new strategies for protecting the environment.

Jennifer Manning | Newswise Science News
Further information:
http://www.acwis.org

More articles from Physics and Astronomy:

nachricht Study offers new theoretical approach to describing non-equilibrium phase transitions
27.04.2017 | DOE/Argonne National Laboratory

nachricht SwRI-led team discovers lull in Mars' giant impact history
26.04.2017 | Southwest Research Institute

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: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Fighting drug resistant tuberculosis – InfectoGnostics meets MYCO-NET² partners in Peru

28.04.2017 | Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

 
Latest News

Wireless power can drive tiny electronic devices in the GI tract

28.04.2017 | Medical Engineering

Ice cave in Transylvania yields window into region's past

28.04.2017 | Earth Sciences

Nose2Brain – Better Therapy for Multiple Sclerosis

28.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>