Stars without magnetic fields?

[flyingcloud]

Hot, dense material surrounds O-type star with largest magnetic field known


http://phys.org/news/2015-09-hot-dense- ... -star.html

From the article:

Only one in 10 massive stars have a magnetic field.

I found this assertion to questionable at best and decided to investigate stars without magnetic fields. I was just wondering how swirling, rotating or otherwise moving plasma could be void of a magnetic field.

I have yet to find examples.

Any ideas?

[BecomingTesla]

The strength of the magnetic field of any star is determined, I *think*, by the degree of polarization of the light being emitted from the object. Taken from the wiki on stellar magnetic fields: "A stellar spectropolarimeter is used to measure the magnetic field of a star. This instrument consists of a spectrograph combined with a polarimeter."

But, here's the issue with the idea that only 1 in 10 of the stars have a magnetic field - the article clearly states that the light being emitted the plasma is being magnetically trapped within the massive magnetosphere of the star itself. If I understand correctly - I am still a student, my answers might not be correct - the article suggests that 80% of the x-ray emissions are being trapped by the star's magnetosphere. I'm not certain, but I'd assume that any other less energetic wavelengths of light are also being trapped. This means that the majority of the light being emitted from the star - and therefore, their ability to measure the star's magnetic field - are being trapped.

So, what happens if in the other O-type stars, rather than only 80% of the x-ray emissions (remember, it's an assumption that the light at other wavelengths are being trapped too), what if its 95%? 99%? How do you possibly measure the magnetic field of the star, when the magnetosphere of the star is so powerful that it continues to trap the light within it?

Without understanding the process of measuring the field better, I can't tell you with any certainty. But, I am also suspect to believe that any star could possibly not have a magnetic field.