Question about Magnetars and neutron stars

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THX1138
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Question about Magnetars and neutron stars

Post by THX1138 » Tue Feb 08, 2022 4:06 am

We create Neodymium magnets using a mixture of different elements and or so called exotic materials, ( that seem to be rather scarce on this rock ) but nonetheless their magnetic effect is nothing compared to what a piece of neutron star would have pound for pound so am I to assume that these stars consist of even more exotic materials than we even know of?
I've come to the conclusion that when i said i wanted to be somebody when i grew up i probably should have been more specific

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Chris Peterson
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Re: Question about Magnetars and neutron stars

Post by Chris Peterson » Tue Feb 08, 2022 4:58 am

THX1138 wrote: Tue Feb 08, 2022 4:06 am We create Neodymium magnets using a mixture of different elements and or so called exotic materials, ( that seem to be rather scarce on this rock ) but nonetheless their magnetic effect is nothing compared to what a piece of neutron star would have pound for pound so am I to assume that these stars consist of even more exotic materials than we even know of?
I've not heard the ordinary elements that magnets are made of described as "exotic". Neodymium is classified as a "rare earth", but it isn't particularly rare.

Neutron stars consist of degenerate matter, which is one class that is commonly labeled "exotic matter".
Chris

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Ann
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Re: Question about Magnetars and neutron stars

Post by Ann » Tue Feb 08, 2022 5:25 am

Chris Peterson wrote: Tue Feb 08, 2022 4:58 am
THX1138 wrote: Tue Feb 08, 2022 4:06 am We create Neodymium magnets using a mixture of different elements and or so called exotic materials, ( that seem to be rather scarce on this rock ) but nonetheless their magnetic effect is nothing compared to what a piece of neutron star would have pound for pound so am I to assume that these stars consist of even more exotic materials than we even know of?
I've not heard the ordinary elements that magnets are made of described as "exotic". Neodymium is classified as a "rare earth", but it isn't particularly rare.

Neutron stars consist of degenerate matter, which is one class that is commonly labeled "exotic matter".
The way I understand it is that one reason why (some) neutron stars are so incredibly magnetic is that giant massive stars that (for some reason) were more magnetic than usual even when they were sustaining themselves through fusion had their magnetic charge incredibly concentrated when their cores shrank to the size of a city like New York.

Is this correct, Chris, or have I misunderstood things?

Ann
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Chris Peterson
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Re: Question about Magnetars and neutron stars

Post by Chris Peterson » Tue Feb 08, 2022 5:50 am

Ann wrote: Tue Feb 08, 2022 5:25 am
Chris Peterson wrote: Tue Feb 08, 2022 4:58 am
THX1138 wrote: Tue Feb 08, 2022 4:06 am We create Neodymium magnets using a mixture of different elements and or so called exotic materials, ( that seem to be rather scarce on this rock ) but nonetheless their magnetic effect is nothing compared to what a piece of neutron star would have pound for pound so am I to assume that these stars consist of even more exotic materials than we even know of?
I've not heard the ordinary elements that magnets are made of described as "exotic". Neodymium is classified as a "rare earth", but it isn't particularly rare.

Neutron stars consist of degenerate matter, which is one class that is commonly labeled "exotic matter".
The way I understand it is that one reason why (some) neutron stars are so incredibly magnetic is that giant massive stars that (for some reason) were more magnetic than usual even when they were sustaining themselves through fusion had their magnetic charge incredibly concentrated when their cores shrank to the size of a city like New York.

Is this correct, Chris, or have I misunderstood things?
Maybe. Simple conservation of magnetic flux is one theory. But it's also possible that some kind of dynamo effect generated the strong field during the collapse, possibly sustained by currents flowing inside the neutron star. Nobody really knows.
Chris

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THX1138
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Re: Question about Magnetars and neutron stars

Post by THX1138 » Thu Feb 10, 2022 1:44 am

Thanks Chris, and Ann for your replies
So let me get this straight, humankind does not rightly know how exactly how magnetars and Neutron stars can be so impossibly.... well, magnetic.
I've come to the conclusion that when i said i wanted to be somebody when i grew up i probably should have been more specific

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Re: Question about Magnetars and neutron stars

Post by neufer » Thu Feb 10, 2022 6:52 pm

The enemy of stellar collapse is angular momentum!

One might assume that:
  • 1) stars with the most angular momentum will also collapse the slowest and, hence,
    allow more time for stellar magnetic fields to escape/reconnect during the collapse process;

    2) while stars with the least angular momentum will collapse the fastest and, hence,
    trap more of the initial stellar magnetic fields into a slowly rotating neutron star.
https://en.wikipedia.org/wiki/Magnetar wrote:
<<Like other neutron stars, magnetars are around 20 kilometres in diameter, and have a mass about 1.4 solar masses. They are formed by the collapse of a star with a mass 10–25 times that of the Sun. Magnetars are differentiated from other neutron stars by having even stronger magnetic fields, and by rotating more slowly in comparison. Most magnetars rotate once every two to ten seconds, whereas typical neutron stars rotate one to ten times per second. The active life of a magnetar is short. Their strong magnetic fields decay after about 10,000 years, after which activity and strong X-ray emission cease.

In a supernova, a star collapses to a neutron star, and its magnetic field increases dramatically in strength through conservation of magnetic flux. Halving a linear dimension increases the magnetic field strength fourfold. Duncan and Thompson calculated that when the spin, temperature and magnetic field of a newly formed neutron star falls into the right ranges, a dynamo mechanism could act, converting heat and rotational energy into magnetic energy and increasing the magnetic field, normally an already enormous 108 teslas, to more than 1011 teslas. The result is a magnetar. It is estimated that about one in ten supernova explosions results in a magnetar rather than a more standard neutron star or pulsar.>>
Art Neuendorffer