Astronomers have found the most magnetic star. The giant magnetic helium star is 3,000 light years away and looks nothing like other helium stars in our universe. Researchers believe that the star could be the key to an ongoing mystery: where do magnetars come from?
Magnetars
Magnetars are a type of neutron star, formed from the incredibly dense remains of massive stars. When the star dies in a supernova, its core collapses. Some of them become magnetars, and they have the strongest known magnetic fields of any object.
Astronomers think that the newly discovered magnetic star could be the forerunner of a magnetar. The star, known as HD 45166, is not a new discovery in itself. However, recent observations have led to a new hypothesis.
Previously, very little was known about the star other than that is located in the binary system, is larger than our sun, and that it shows some characteristics of a Wolf-Rayet star (another name for a helium star). The fact that it does not look the same as other helium stars has perplexed researchers. The lead author of the new study, Toner Shenar thought this warranted more research. He suspected the reason HD 45166 looked different was because it was a magnetic star.
An artist’s impression of a magnetar. Image: Shutterstock
The strongest magnetic field
Spectroscopic observations from telescopes revealed the scale of HD 45166’s magnetic field, a staggering 43,000 gauss. For comparison, a fridge magnet has a strength of approximately 100 gauss, and the Earth’s magnetic field ranges between 0.25 and 0.65 gauss.
The research team thinks the magnetic field varies based on how a helium star forms. Most evolve from red supergiants, but they think this star was formed when two medium-mass stars merged together.
This magnetic field is affecting material that would usually flow away from the star. “What you would see up close is mostly material trapped in arcs going between the poles of the star and colliding in the middle. You’d see this thick ball of gas, and sometimes piercing through this you’d see the actual star,” Shenar told New Scientist.
When stars become neutron stars and their cores collapse, their magnetic field is amplified. Previously, astronomers had never found a star with a magnetic field strong enough to become a magnetar during this process. This is what makes this particular star so interesting. In a few million years, HD 45166 will collapse in on itself and the team believes it will become a magnetar. When this happens, its magnetic field will strengthen to approximately 100 trillion gauss.
