How it deternined if a Star has Magnetism if heat does not support magnetism?

Answer 1

Magnetism can be generated in more than one way.

In a solid object if all the atoms have most of their poles lined up in the same direction the object has a magnetic field. It's how most everyday magnets work.

An electrical charge in a loop can generate a magnetic field. Large electric motors use this route. They use a coil of conductive metal, but the principal still works in any charged medium.

With stars the medium is shifting loops of plasma. Plasma is just a gas with the electrons stripped out because of intense heat and or electromagnetic radiation. The loops are an effect of the stars rotation.

Answer 2

I don't know how they measure a star's magnetic field, but heat doesn't rule out the presence of magnetism. Any flow of electricity moving through space creates a magnetic field, and that includes the flow of electricity through plasma, or inside a star whatever it's made of. Don't confuse this with the Curie point, where a metal loses it's magnetic properties. The metal is still capable of conducting electricity, and if there is a current flowing through it, there is a magnetic field whether or not the metal itself is magnetic or not. After all, copper isn't magnetic. But wound into a coil and conducting electricity, it makes very powerful magnets.

Answer 3

Magnetic fields are detected by their influence on charged particles (ions, electrons, protons) in the vicinity of a star.
Magnetic fields also influences the polarization of light from the star as well as the frequencies of high-energy radiation (X-rays, gamma rays) from the star or passing by the star - all of these are detectable with different telescopes.

Answer 4

If the light coming from the star is polarized, the star must have a magnetic field. Nearly all stars do.