Researchers theorize origins of magnetars, the strongest magnets in the universe

How do the strongest magnets in the universe form?
The simulation marks the birth of a magnetic star such as Tau Scorpii. The image is a cut through the orbital plane where the colouring indicates the strength of the magnetic field and the light hatching reflects the direction of the magnetic field line. Credit: Ohlmann/Schneider/Röpke

How do some neutron stars become the strongest magnets in the universe? A German-British team of astrophysicists has found a possible answer to the question of how magnetars form. They used large computer simulations to demonstrate how the merger of two stars creates strong magnetic fields. If such stars explode in supernovae, magnetars can result. Scientists from Heidelberg University, the Max Planck Society, the Heidelberg Institute for Theoretical Studies, and the University of Oxford were involved in the research. The results were published in Nature.

The universe is threaded by magnetic fields. The sun, for example, has an envelope in which convection continuously generates magnetic fields. "Even though massive stars have no such envelopes, we still observe a strong, large-scale magnetic field at the surface of about 10 percent of them," explains Dr. Fabian Schneider from the Centre for Astronomy of Heidelberg University, who is the first author of the study in Nature. Although such fields were discovered in 1947, their origin has remained elusive so far.

Over a decade ago, scientists suggested that are produced when two stars collide. "But until now, we weren't able to test this hypothesis because we didn't have the necessary computational tools," says Dr. Sebastian Ohlmann from the computing centre of the Max Planck Society in Garching near Munich. This time, the researchers used the AREPO code, a highly dynamic simulation code running on computer clusters of the Heidelberg Institute for Theoretical Studies (HITS), to explain the properties of Tau Scorpii (τ Sco), a magnetic star located 500 from Earth.

How do the strongest magnets in the universe form?
The simulation marks the birth of a magnetic star such as Tau Scorpii. The image is a cut through the orbital plane where the coloring indicates the strength of the magnetic field and the light hatching reflects the direction of the magnetic field line. Credit: Ohlmann/Schneider/Röpke

In 2016, Fabian Schneider and Philipp Podsiadlowski from the University of Oxford realised that τ Sco is a so-called blue straggler. Blue stragglers are the product of merged stars. "We assume that Tau Scorpii obtained its strong magnetic field during the merger process," explains Prof. Dr. Philipp Podsiadlowski. Through its computer simulations of τ Sco, the German-British research team has now demonstrated that strong turbulence during the merger of two stars can create such a field.

Stellar mergers are relatively frequent. Scientists assume that about 10 percent of all massive stars in the Milky Way are the products of such processes. This is in good agreement with the occurrence rate of magnetic , according to Dr. Schneider. Astronomers think that these very could form magnetars when they explode in supernovae.

This may also happen to τ Sco when it explodes at the end of its life. The computer simulations suggest that the magnetic field generated would be sufficient to explain the exceptionally strong magnetic fields in magnetars. "Magnetars are thought to have the strongest magnetic fields in the universe—up to 100 million times stronger than the strongest ever produced by humans," says Friedrich Röpke from HITS.


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More information: Stellar mergers as the origin of magnetic massive stars, Nature (2019). DOI: 10.1038/s41586-019-1621-5 , https://nature.com/articles/s41586-019-1621-5
Journal information: Nature

Citation: Researchers theorize origins of magnetars, the strongest magnets in the universe (2019, October 9) retrieved 20 October 2019 from https://phys.org/news/2019-10-theorize-magnetars-strongest-magnets-universe.html
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Oct 09, 2019
It would have been nice if the mechanism for creating the large magnetic field was given...something more descriptive than "the merger of two stars".


Oct 10, 2019
What causes magnetic fields? Gee, I wonder. What about Electric currents? How can electric currents exist in space? How about Birkeland plasma currents?

Everything astronomers think they know about stars is wrong. They're not driven by fussion deep inside its core, but by plasma discharge on the surface, powered by interstellar birkeland currents. How do I know? Because the Safire project was an independant audit of the theory of the electric sun. They basically created a sun in a test tube, complete with a photosphere that is million degrees hot and fussion happening in the plasma, creating the very same elements we observe in the sun.

Meanwhile, mainstream scientists are still playing arround with computer models, using an incomplete toolbox of physical forces, trying to make obsolete theories work.

Oct 10, 2019
What causes magnetic fields? Gee, I wonder. What about Electric currents? How can electric currents exist in space? How about Birkeland plasma currents?

Show me the electric currents or birkeland plasma currents powering my fridge magnets.

They basically created a sun in a test tube, complete with a photosphere that is million degrees hot and fussion happening in the plasma, creating the very same elements we observe in the sun.

Is this the case where the sun has a metallic ball inside it? I have never seen anyone proofing it exists in the sun.

Oct 10, 2019
Everything astronomers think they know about stars is wrong. They're not driven by fussion deep inside its core, but by plasma discharge on the surface, powered by interstellar birkeland currents. How do I know? Because the Safire project was an independant audit of the theory of the electric sun. They basically created a sun in a test tube, complete with a photosphere that is million degrees hot and fussion happening in the plasma, creating the very same elements we observe in the sun.

Meanwhile, mainstream scientists are still playing arround with computer models, using an incomplete toolbox of physical forces, trying to make obsolete theories work.


Lol. SAFIRE put a squillion volts through a metallic sphere! Who cares? They written it up yet? Will they ever? What were their neutrino counts? What was their solar wind composed of? Where is the current powering this woo in the solar system? Why can't we see it? How is it getting past the solar wind? And the IMF? Et cetera.

Oct 10, 2019
It would have been nice if the mechanism for creating the large magnetic field was given...something more descriptive than "the merger of two stars".


Dynamo processes within stars create the fields. The fields can then propagate outwards. Ours is carried all the way to the heliopause by the solar wind.

Understanding the solar dynamo
Paul Bushby & Joanne Mason
https://academic..../1746086

Oct 10, 2019
The magnetic fields of magnetars are truly staggering. Wikipedia has these (theorized) at 10^9 to 10^11 Tesla

For comparison. If you've ever experienced the enormous pull a magnetic resonance imaging machine can produce...the base filed of the ones currently installed in hospitals range - depending on model - between 1.5 and 7 Tesla.

Future cosmonaut safety tipp: Don't fly close to one with a pacemaker.

Oct 10, 2019
This is a very elegant result! "... the German-British research team has now demonstrated that strong turbulence during the merger of two stars can create such a field.

Stellar mergers are relatively frequent. Scientists assume that about 10 percent of all massive stars in the Milky Way are the products of such processes. This is in good agreement with the occurrence rate of magnetic massive stars, ..."

@Banal Resentive: The cause was described, collision caused turbulence. AFAIK turbulent MHD plasma cause strong magnetic fields (and vice versa).

Admittedly, they could have described it better, but it is in the paper if you are curious.

Oct 10, 2019
Everything astronomers think they know about stars is wrong.


LOL!

An erroneous claim, of course. The rest of us see that what astronomers knew has passed yet another test and is even stronger - the collision was driven by gravity (which orders the universe according to modern cosmology) and the turbulent plasma is driven by fusion - while magnetic fields are relegated to be the wagging tail of that dog. Now we have not only observation but theory telling us why just 10 % of neutron stars are magnetars, not the 100 % that you need for making strong magnetism ubiquitous: now we are even more sure that magnetism is just contingent on the system.

What a fail. Why do you even troll?

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