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[Vasilis]

Anything that can be answered quickly. Maybe Google wasn't very specific or you didn't answerstand it's answer.

[Jay]

How does a magnetar get its angular momentum? Hope this question gets along as "easy". 😉

[Vasilis]

On 5/22/2019 at 5:23 AM, BrotherJay said:

How does a magnetar get its angular momentum? Hope this question gets along as "easy". 😉

Excactly the same way regular neutron stars do and black holes do. The reason it has more that usual neutron stars comes down to propability.

 

Magnetars and regular neutron stars and black holes, have the same angular momentum their parent star had. The thing they have more is angular velocity. Angular momentum doesn't change in a closed system. So when a star becomes a neutron star since it doesn't interact with objects it's angular momentum stays constant.

 

Now why do neutron stars have huge angular velocities? Well, watch this skater: https://www.youtube.com/watch?v=jeB4aAVQMug. How did she went from spining slowly to spining fast? Did she push with her leg? NO! What she did is contract her leg and hand. When you change your shape from wide to narrow you hold your angular momentum constant but increase angular velocity.

 

That's excactly what neutron stars do. Their parent star volume is huge. But when they become the size of Manhatan their angular velocity skyrockets to speeds comparable to the speed of light. Not all neutron stars have the same angular velocity because not all stars are the same. The top 10% of them we decided to call them Magnetars.