Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Stellar waltz with dramatic ending

22.05.2019

Researchers of the University of Bonn identify extremely rare fusion of two white dwarfs

Astronomers at the University of Bonn and their colleagues from Moscow have identified an unusual celestial object. It is most likely the product of the fusion of two stars that died a long time ago.


WISE 22 micron infrared images at different intensity scales (panels a and b) compared with an optical IPHAS H alpha image where the nebula is not visible (panel c).

Credit: (c) Vasilii Gvaramadse/Moscow University

Usage Restrictions: This photo may be used with the press release.

After billions of years circling around each other these so-called white dwarfs merged and rose from the dead. In the near future, their lives could finally end - with a huge bang. The researchers are now presenting their findings in the journal Nature.

The extremely rare merger product was discovered by scientists from the University of Moscow. On images made by the Wide-field Infrared Survey Explorer (WISE) satellite they found a gas nebula with a bright star in its center. Surprisingly, however, the nebula emitted almost exclusively infrared radiation and no visible light.

"Our colleagues in Moscow realized that this already argued for an unusual origin", explains Dr. Götz Gräfener from the Argelander Institute for Astronomy (AIfA) at the University of Bonn.

In Bonn, the spectrum of the radiation emitted by the nebula and its central star was analyzed. In this way, the AIfA researchers were able to show that the enigmatic celestial object contained neither hydrogen nor helium - a characteristic typical for the interiors of white dwarfs.

Stars like our Sun generate their energy through hydrogen burning, the nuclear fusion of hydrogen. When the hydrogen is consumed, they continue burning helium.

However, they cannot fuse even heavier elements - their mass is insufficient to produce the necessary high temperatures. Once all helium is used up, they cease burning and cool down turning into so-called white dwarfs.

Usually their life is over at this point. But not for J005311 - this is how the scientists named their new find in the constellation Cassiopeia, 10,000 light-years from Earth.

"We assume that two white dwarfs formed there in close proximity many billions of years ago," explains Prof. Dr. Norbert Langer from AIfA. "They circled around each other, creating exotic distortions of space-time, called gravitational waves." In the process, they gradually lost energy. In return, the distance between them shrunk more and more until they finally merged.

Only five of these objects in the Milky Way

Now their total mass was sufficient to fuse heavier elements than hydrogen or helium. The stellar furnace started burning again. "Such an event is extremely rare," stresses Gräfener. "There are probably not even half a dozen such objects in the Milky Way, and we have discovered one of them."

An extreme stroke of luck. Nevertheless, the researchers are convinced that they are right with their interpretation. For one, the star in the center of the nebula shines 40,000 times as bright as the sun, far brighter than a single white dwarf could.

In addition, the spectra indicate that J005311 has an extremely strong stellar wind - this is the stream of material that emanates from the stellar surface. Its engine is the radiation generated during the burning process.

Only, at a speed of 16,000 kilometers per second, the wind of J005311 is so fast that this factor alone is not enough to explain it. However, merged white dwarfs are expected to have a very strong rotating magnetic field. "Our simulations show that this field acts like a turbine, which additionally accelerates the stellar wind," says Gräfener.

Sadly, the resurgence of J005311 will not last long. In only a few thousand years the star will have transformed all elements into iron and fade again. As its mass has increased to more than 1.4 times the mass of the Sun in the merger process, it will suffer an exceptional fate.

The star will collapse under the influence of its own gravity. At the same time, the electrons and protons building up its matter will fuse into neutrons. The resulting neutron star has only a fraction of its previous size, measuring only few kilometers in diameter, while it is weighing more than the entire solar system.

J005311, however, won't leave without a final salute. Its collapse will be accompanied by a huge bang, a so-called supernova explosion.

###

Publication: Vasilii V. Gvaramadze, Götz Gräfener, Norbert Langer, Olga V. Maryeva, Alexei Y. Kniazev, Alexander S. Moskvitin & Olga I. Spiridonova: A massive white-dwarf merger product before final collapse; Nature, https://doi.org/10.1038/s41586-019-1216-1

Contact:

Dr. Götz Gräfener
Argelander Institute for Astronomy at the University of Bonn.
Tel. +49-228-733651
E-mail: goetz@astro.uni-bonn.de

Prof. Dr. Norbert Langer
Argelander Institute for Astronomy at the University of Bonn.
Max Planck Institute for Radio Astronomy
Tel. +49-228-733656
E-mail: nlanger@astro.uni-bonn.de

Dr. Götz Gräfener | EurekAlert!
Further information:
http://dx.doi.org/10.1038/s41586-019-1216-1

More articles from Physics and Astronomy:

nachricht Immortal quantum particles: the cycle of decay and rebirth
14.06.2019 | Technische Universität München

nachricht Small currents for big gains in spintronics
13.06.2019 | University of Tokyo

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: MPSD team discovers light-induced ferroelectricity in strontium titanate

Light can be used not only to measure materials’ properties, but also to change them. Especially interesting are those cases in which the function of a material can be modified, such as its ability to conduct electricity or to store information in its magnetic state. A team led by Andrea Cavalleri from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg used terahertz frequency light pulses to transform a non-ferroelectric material into a ferroelectric one.

Ferroelectricity is a state in which the constituent lattice “looks” in one specific direction, forming a macroscopic electrical polarisation. The ability to...

Im Focus: Determining the Earth’s gravity field more accurately than ever before

Researchers at TU Graz calculate the most accurate gravity field determination of the Earth using 1.16 billion satellite measurements. This yields valuable knowledge for climate research.

The Earth’s gravity fluctuates from place to place. Geodesists use this phenomenon to observe geodynamic and climatological processes. Using...

Im Focus: Tube anemone has the largest animal mitochondrial genome ever sequenced

Discovery by Brazilian and US researchers could change the classification of two species, which appear more akin to jellyfish than was thought.

The tube anemone Isarachnanthus nocturnus is only 15 cm long but has the largest mitochondrial genome of any animal sequenced to date, with 80,923 base pairs....

Im Focus: Tiny light box opens new doors into the nanoworld

Researchers at Chalmers University of Technology, Sweden, have discovered a completely new way of capturing, amplifying and linking light to matter at the nanolevel. Using a tiny box, built from stacked atomically thin material, they have succeeded in creating a type of feedback loop in which light and matter become one. The discovery, which was recently published in Nature Nanotechnology, opens up new possibilities in the world of nanophotonics.

Photonics is concerned with various means of using light. Fibre-optic communication is an example of photonics, as is the technology behind photodetectors and...

Im Focus: Cost-effective and individualized advanced electronic packaging in small batches now available

Fraunhofer IZM is joining the EUROPRACTICE IC Service platform. Together, the partners are making fan-out wafer level packaging (FOWLP) for electronic devices available and affordable even in small batches – and thus of interest to research institutes, universities, and SMEs. Costs can be significantly reduced by up to ten customers implementing individual fan-out wafer level packaging for their ICs or other components on a multi-project wafer. The target group includes any organization that does not produce in large quantities, but requires prototypes.

Research always means trying things out and daring to do new things. Research institutes, universities, and SMEs do not produce in large batches, but rather...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

SEMANTiCS 2019 brings together industry leaders and data scientists in Karlsruhe

29.04.2019 | Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

First dust conference in the Central Asian part of the earth’s dust belt

15.04.2019 | Event News

 
Latest News

Concert of magnetic moments

14.06.2019 | Information Technology

Materials informatics reveals new class of super-hard alloys

14.06.2019 | Materials Sciences

New imaging modality targets cholesterol in arterial plaque

14.06.2019 | Medical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>