Studying the Magnetic Fields of New Stars
Stars begin as clouds of gas in space. The gravitational collapse that will form the star begins because of the cold temperatures and high density of these clouds. Before reaching star status, this ball of gas’s core must be hot enough for the fusion that powers it to take place. Until then, it’s just a protostar.
For years, scientists thought that the magnetic fields swirling around burgeoning planets were concrete and unyielding, confining star-forming clouds of gas. However, using the Atacama Large Millimeter/submillimeter Array telescope, or ALMA, a team of researchers has discovered a “weak and wildly disorganized magnetic field” surrounding a newly formed protostar. The protostar, named Ser-emb 8, lives around 1,400 light years away from us in the Serpens constellation.
While seeing this in action could give us a glimpse into what our solar system looked like when it was new, this discovery could also allow us more detailed insights into the magnetic fields of young stars.
Previously, it was thought that stars could only emerge in certain conditions, namely, in strong magnetic fields. Now, it’s becoming clear that these parameters don’t have to be quite so strict. Past observations using telescopes have shown the magnetic fields surrounding protostars are hourglass-shaped, extending out for light years into the cloud.
As it ages, material outflowing from the star disrupts the early magnetic field, erasing its signature and making it impossible for researchers to study. The original cloud of gas is absorbed partially by the star itself and any surrounding planets. The rest can be blown away by solar winds. ALMA can reveal the magnetic field before all of this expunging happens.
In the case of Ser-emb 8, researchers believe that they have caught the protostar’s magnetic field in its earliest stages before other material from the star could tamper with the magnetic it’s signature in the surrounding molecular cloud. ALMA was able to map the magnetic field by tracing the polarized light emitted by dust grains that lined up with the magnetic field over time.
What does this mean?
These studies show that the importance of the magnetic field could vary from star to star. While the data is sparse now, further observations will show how common different variations are in terms of the patterns, size, and strength of the magnetic fields.
We’ll keep you updated on any further findings. Until then, keep an eye on our News & How-Tos section for more interesting magnet related news and DIY projects.