Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Detonating white dwarfs as supernovae

06.10.2016

A new mathematical model created by astrophysicists at the American Museum of Natural History, New York, describes how dead stars called white dwarfs could detonate, producing a type of explosion that is instrumental to measuring the extreme distances in our universe. The mechanism, described in a paper in Monthly Notices of the Royal Astronomical Society, could improve our understanding of how Type Ia supernovae form.

“Type Ia supernovae are extremely important objects in physics, best known for their role in revealing that the expansion of the universe is accelerating,” said paper co-author Saavik Ford, who is a research associate in the Museum’s Department of Astrophysics as well as a professor at the Borough of Manhattan Community College, City University of New York (CUNY); a faculty member at CUNY’s Graduate Center; and a Kavli Scholar at the Kavli Institute for Theoretical Physics. “The problem is that people do not agree on exactly how Type Ia supernovae come to be.”


Hubble Space Telescope image of the type Ia supernova 1994D (lower left) in galaxy NGC 4526. Credit: NASA/ESA, the Hubble Key Project Team and the High-Z Supernova Search Team

Current research indicates that Type Ia supernova explosions originate from binary star systems—two stars orbiting one another—in which at least one star is a white dwarf, the dense remains of a star that was a few times more massive than our Sun. For this study, the scientists investigated how two white dwarfs might form a supernova.

“The simplest way to create a Type Ia supernova is to run two white dwarfs into one another,” Ford said. “In our local universe, there are very few white dwarf binaries that are close enough to collide. Yet we see lots of supernovae lighting up our universe, so we know that something else is probably going on to cause those explosions.”

Ford and co-author Barry McKernan, who is also a research associate in the Museum’s Department of Astrophysics, a professor at the Borough of Manhattan Community College, CUNY, a faculty member at CUNY’s Graduate Center, and a Kavli Scholar at the Kavli Institute for Theoretical Physics, propose the following: White dwarfs are roughly Earth-sized balls of dense, compressed, degenerate matter that wobble, or oscillate.

When two white dwarfs orbit each other they tug on one another, emitting gravitational radiation that takes away energy from their orbit. This causes them to get closer and closer together. During this process, known as inspiraling, the binary orbit of the stars gets smaller, the frequency of the tugging gets stronger and, at certain “sweet spots,” it matches an oscillation frequency in at least one of the white dwarfs. When this happens, a phenomenon called resonance is produced, which can be visualised by a child being pushed in a playground swing.

“Pushing your kid in time with the natural interval, or frequency, of the swing ramps up the energy and gets them higher and higher,” McKernan said. “There’s a similar effect in our model, where a lock on the frequency produces a series of rapid jumps in energy that are deposited into the white dwarfs.”
As a result, if enough energy is deposited in the resonating white dwarf, it could explode before it touches the other one. If the white dwarf does not explode, the resonance causes the orbit to shrink faster than predicted by gravitational wave emission alone, so the stars will crash into each other faster than would normally be expected.

“Basically, we’ve proposed that if you have two white dwarfs spiralling towards each other and you shake one of them the right way for long enough, one will either blow up or you’ll bring the objects closer together faster for an eventual detonation,” McKernan said.

Ford and McKernan plan to test their model by combing through data produced by up-and-coming gravitational wave detectors like eLISA, a space-based observatory expected to launch in 2029.
“If we’re right, eLISA may be able to see glitches in the gravitational waveforms coming from some of the nearest white dwarf binaries,” McKernan said. “That would be amazing to see.”

Further information

Funding for this study was provided by the National Science Foundation grant #s PAARE AST-1153335 and PHY11-25915.

The new work appears in “On the resonant detonation of sub-Chandrasekhar mass white dwarfs during binary inspiral”, B. McKernan and K. E. S. Ford, vol. 463 (2), pp. 2039-2045, Monthly Notices of the Royal Astronomical Society, Oxford University Press. A copy of the paper is available from http://mnras.oxfordjournals.org/content/463/2/2039

http://www.ras.org.uk

  • Full bibliographic informationThe new work appears in “On the resonant detonation of sub-Chandrasekhar mass white dwarfs during binary inspiral”, B. McKernan and K. E. S. Ford, vol. 463 (2), pp. 2039-2045, Monthly Notices of the Royal Astronomical Society, Oxford University Press. A copy of the paper is available from http://mnras.oxfordjournals.org/content/463/2/2039

For further information, please contact:

Robert Massey

+44 (0)20 7734 3307

rm@ras.org.uk

Robert Massey | AlphaGalileo

Further reports about: Type Ia supernovae astrophysics supernovae white dwarf

More articles from Physics and Astronomy:

nachricht Engineering team images tiny quasicrystals as they form
18.08.2017 | Cornell University

nachricht Astrophysicists explain the mysterious behavior of cosmic rays
18.08.2017 | Moscow Institute of Physics and Technology

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: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

Engineering team images tiny quasicrystals as they form

18.08.2017 | Physics and Astronomy

Researchers printed graphene-like materials with inkjet

18.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>