Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Are Stellar Explosions Created Equal?

22.08.2011
Scientists recheck a standard model for supernovae on which cosmic distance measurement is based

Cosmic distances are difficult to grasp and no less difficult to measure. When it comes to other galaxies or even remote parts of our own Milky Way, distance measurements are nothing but assessments, derived from indirect clues.

Highly important among such clues are supernovae, extremely luminous stellar explosions. The distance to a supernova of a particular type, called Type Ia, can be calculated from its brightness: the brighter it appears, the closer it is to the viewer. Thanks to such supernovae, for example, astronomers have famously revealed that our universe is expanding at an accelerated pace, which suggests that it’s permeated with mysterious dark energy. These calculations, however, are based on the assumption that all Type Ia supernovae have the same luminosity. Are all these explosions indeed created equal?

Type Ia supernovae are thought to be born when an exceedingly dense star called a white dwarf receives more mass from a nearby star, until it’s so ‘overwhelmed’ that it explodes. A new study reported in Science and led by Weizmann Institute researchers, has gained major insight into the nature of these mass ‘donors.’ The study was performed by Dr. Avishay Gal-Yam and postdoctoral fellow Dr. Assaf Sternberg of Weizmann’s Particle Physics and Astrophysics Department, in collaboration with scientists from more than a dozen research centers in the United States, Europe and Australia.

The researchers have revealed that in about a quarter of the cases in spiral galaxies, and possibly more, the companion star that ‘donates’ its mass to the white dwarf is probably a regular, medium-sized star, largely similar to our own Sun. They reached this conclusion by analyzing the outflow of gas, typical of sun-like stars, observed during the ‘donation’ of the mass. These findings constitute a major step toward determining the nature of all stellar ‘donors,’ with the ultimate goal of establishing whether supernovae everywhere evolve in the same manner, having the same luminosity at various stages. Understanding their evolution, in turn, can greatly enhance our ability to measure distances throughout the cosmos and map its evolution and geometry.

Dr. Avishay Gal-Yam’s research is supported by the Nella and Leon Benoziyo Center for Astrophysics; the Yeda-Sela Center for Basic Research; the Peter and Patricia Gruber Award; the Legacy Heritage Fund Program of the Israel Science Foundation; Miel de Botton Aynsley, UK; and the Lord Sieff of Brimpton Memorial Fund.

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 2,700 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.

Weizmann Institute news releases are posted on the World Wide Web at http://wis-wander.weizmann.ac.il, and are also available at http://www.eurekalert.org.

Batya Greenman | idw
Further information:
http://wis-wander.weizmann.ac.il

More articles from Physics and Astronomy:

nachricht Illinois team finds Wigner crystal -- not Mott insulator -- in 'magic-angle' graphene
25.09.2018 | University of Illinois College of Engineering

nachricht Measuring Smallest Magnetic Fields in the Brain Using Diamond and Laser Technology
25.09.2018 | Fraunhofer-Institut für Angewandte Festkörperphysik IAF

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: Working the switches for axon branching

Our brain is a complex network with innumerable connections between cells. Neuronal cells have long thin extensions, so-called axons, which are branched to increase the number of interactions. Researchers at the Max Planck Institute of Biochemistry (MPIB) have collaborated with researchers from Portugal and France to study cellular branching processes. They demonstrated a novel mechanism that induces branching of microtubules, an intracellular support system. The newly discovered dynamics of microtubules has a key role in neuronal development. The results were recently published in the journal Nature Cell Biology.

From the twigs of trees to railroad switches – our environment teems with rigid branched objects. These objects are so omnipresent in our lives, we barely...

Im Focus: Hygiene at your fingertips with the new CleanHand Network

The Fraunhofer FEP has been involved in developing processes and equipment for cleaning, sterilization, and surface modification for decades. The CleanHand Network for development of systems and technologies to clean surfaces, materials, and objects was established in May 2018 to bundle the expertise of many partnering organizations. As a partner in the CleanHand Network, Fraunhofer FEP will present the Network and current research topics of the Institute in the field of hygiene and cleaning at the parts2clean trade fair, October 23-25, 2018 in Stuttgart, at the booth of the Fraunhofer Cleaning Technology Alliance (Hall 5, Booth C31).

Test reports and studies on the cleanliness of European motorway rest areas, hotel beds, and outdoor pools increasingly appear in the press, especially during...

Im Focus: Scientists present new observations to understand the phase transition in quantum chromodynamics

The building blocks of matter in our universe were formed in the first 10 microseconds of its existence, according to the currently accepted scientific picture. After the Big Bang about 13.7 billion years ago, matter consisted mainly of quarks and gluons, two types of elementary particles whose interactions are governed by quantum chromodynamics (QCD), the theory of strong interaction. In the early universe, these particles moved (nearly) freely in a quark-gluon plasma.

This is a joint press release of University Muenster and Heidelberg as well as the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt.

Then, in a phase transition, they combined and formed hadrons, among them the building blocks of atomic nuclei, protons and neutrons. In the current issue of...

Im Focus: Patented nanostructure for solar cells: Rough optics, smooth surface

Thin-film solar cells made of crystalline silicon are inexpensive and achieve efficiencies of a good 14 percent. However, they could do even better if their shiny surfaces reflected less light. A team led by Prof. Christiane Becker from the Helmholtz-Zentrum Berlin (HZB) has now patented a sophisticated new solution to this problem.

"It is not enough simply to bring more light into the cell," says Christiane Becker. Such surface structures can even ultimately reduce the efficiency by...

Im Focus: New soft coral species discovered in Panama

A study in the journal Bulletin of Marine Science describes a new, blood-red species of octocoral found in Panama. The species in the genus Thesea was discovered in the threatened low-light reef environment on Hannibal Bank, 60 kilometers off mainland Pacific Panama, by researchers at the Smithsonian Tropical Research Institute in Panama (STRI) and the Centro de Investigación en Ciencias del Mar y Limnología (CIMAR) at the University of Costa Rica.

Scientists established the new species, Thesea dalioi, by comparing its physical traits, such as branch thickness and the bright red colony color, with the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

"Boston calling": TU Berlin and the Weizenbaum Institute organize a conference in USA

21.09.2018 | Event News

One of the world’s most prominent strategic forums for global health held in Berlin in October 2018

03.09.2018 | Event News

4th Intelligent Materials - European Symposium on Intelligent Materials

27.08.2018 | Event News

 
Latest News

New enclosure gives a boost to electrical engineering companies

26.09.2018 | Trade Fair News

Working the switches for axon branching

26.09.2018 | Life Sciences

Establishing metastasis

25.09.2018 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>