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 Space radiation won't stop NASA's human exploration
18.10.2017 | NASA/Johnson Space Center

nachricht Study shows how water could have flowed on 'cold and icy' ancient Mars
18.10.2017 | Brown University

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: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Osaka university researchers make the slipperiest surfaces adhesive

18.10.2017 | Materials Sciences

Space radiation won't stop NASA's human exploration

18.10.2017 | Physics and Astronomy

Los Alamos researchers and supercomputers help interpret the latest LIGO findings

18.10.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>