Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

University of Arizona Astronomer Helps Discover New Supernova Type

25.05.2010
The finding sheds light on some universal mysteries, including the possibility that exploding stars created some of the matter that makes up our bodies.

Not all explosions are created equal – it's as true for film effects as it is for stars. An international team of scientists, including a University of Arizona astronomer, has identified a third type of exploding star, or supernova.

Until now, scientists had only observed two kinds of supernovae – either hot, young giants that go out in a violent display as they collapse under their own weight, or old, dense white dwarves that blow up in a thermonuclear explosion. The new supernova appeared in telescope images in January 2005. Seeing that it had recently begun the process of exploding, scientists started collecting and combining data from different telescope sites around the world, measuring both the amount of material thrown off in the explosion and its chemical makeup. The team, led by principal investigator Avishay Gal-Yam at the Weizmann Institute of Science in Rehovot, Israel, soon found that the new supernova did not fit either of the known patterns.

"Such events were predicted but never observed until now," said team member David Arnett, a Regents' Professor of Astronomy at the University of Arizona’s Steward Observatory. A senior theorist on the paper, Arnett performed calculations that explained the puzzling distributions of chemical elements in the supernova remnant, the "smoking gun" of the stellar explosion. The findings appeared in the May 20 issue of the journal Nature.

Working like detectives on a crime scene of cosmic proportions, the team deciphered the evidence and reconstructed the events leading to the star's demise. By analyzing the spectral pattern of light coming from the supernova, they sifted through the thermonuclear ashes to infer the conditions under which the explosion unfolded, even to the point of identifying the progenitor as a helium-rich white dwarf that detonated.

On one hand, the amount of material hurled out from the supernova was too small for it to have come from an exploding giant. In addition, its location, distant from the busy hubs where new stars form, implied it was an older star that had had time to wander off from its birthplace. On the other hand, its chemical makeup didn't match that commonly seen in the second type.

"It was clear," said the paper's lead author Hagai Perets, "that we were seeing a new type of supernova."

The scientists turned to computer simulations to see what kind of process could have produced such a result. The common type of exploding white dwarf (a type Ia supernova) is mainly made up of carbon and oxygen, and the chemical composition of the ejected material reflects this. The newly discovered supernova had unusually high levels of the elements calcium and titanium; these are the products of a nuclear reaction involving helium, rather than carbon and oxygen.

Where did the helium come from? The simulations suggest that a pair of white dwarfs are involved; one of them stealing helium from the other. When the thief star's helium load rises past a certain point, the explosion occurs.

"The donor star is probably completely destroyed in the process, but we're not quite sure about the fate of the thief star," said Gal-Yam.

"This supernova confirms my old idea that there should be several ways that supernova explosions could happen, and that we should observe a variety of events," Arnett said. "This event was classified in a group that included vastly different explosions, including core collapse supernovae, which make a neutron star or black hole, and detonations of white dwarfs made of carbon and oxygen."

The scientists believe that several other previously observed supernovae may fit this pattern. In fact, these relatively dim explosions might not be all that rare; if so, their occurrence could explain some puzzling phenomena in the universe.

For example, almost all the elements heavier than hydrogen and helium have been created in and dispersed by supernovae; the new type could help explain the prevalence of calcium in both the universe and in our bodies.

"Observations like this are beginning to sort out the complexity that we see out there," Arnett said.

It might also account for observed concentrations of particles called positrons in the center of our galaxy. Positrons are identical to electrons, but with an opposite charge, and some have hypothesized that the decay of yet unseen "dark matter" particles may be the cause of their presence. But one of the products of the new supernova is a radioactive form of titanium that, as it decays, emits positrons.

"Dark matter may or may not exist," said Gal-Yam, "but these positrons are perhaps just as easily accounted for by the third type of supernova."

Other members of the research team include Paolo Mazzali of the Max-Planck Institute for Astrophysics in Germany; the Scuola Normale Superiore, Pisa; and the INAF/Padova Observatory in Italy. Additional researchers from the U.S., Canada, Chile and the UK also contributed.

Jennifer Fitzenberger | University of Arizona
Further information:
http://www.arizona.edu

Further reports about: Astronomer Gal-Yam Observatory Supernova computer simulation discover white dwarf

More articles from Physics and Astronomy:

nachricht From rocks in Colorado, evidence of a 'chaotic solar system'
23.02.2017 | University of Wisconsin-Madison

nachricht Prediction: More gas-giants will be found orbiting Sun-like stars
22.02.2017 | Carnegie Institution for Science

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: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

From rocks in Colorado, evidence of a 'chaotic solar system'

23.02.2017 | Physics and Astronomy

'Quartz' crystals at the Earth's core power its magnetic field

23.02.2017 | Earth Sciences

Antimicrobial substances identified in Komodo dragon blood

23.02.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>