Monday, July 24, 2017

Chaotically Magnetized Cloud Is No Place to Build a Star, or Is It? - UNIVERSE

For decades, scientists believed that the magnetic field lines around a forming star were extremely powerful and orderly, warping only under extreme force and at great distance from the nascent star.

Now, a team of astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) has discovered a weak and wildly disorganized magnetic field strikingly near a newly emerging protostar. These observations suggest that the impact of magnetic fields on star formation is more complex than previously thought.

The researchers used ALMA to map the surprisingly disorganized magnetic field surrounding a young protostar dubbed Ser-emb 8, which resides about 1400 light-years away in the Serpens star-forming region. These new observations are the most sensitive ever made of the small-scale magnetic field suffusing the region surrounding a young forming star. They also provide important insights into the formation of low-mass stars like own sun.

Previous observations with other telescopes have confirmed that magnetic fields surrounding some young protostars form a classic “hourglass” shape – a hallmark of a strong magnetic field – that starts near the protostar and extends many light-years into the surrounding molecular cloud.

“Before now, we didn’t know if all stars formed in regions that were controlled by strong magnetic fields. Using ALMA, we found our answer,” said Charles L. H. “Chat” Hull, an astronomer and NRAO Jansky Fellow at the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, Mass., and lead author on a paper appearing in the Astrophysical Journal Letters. “We can now study magnetic fields in star-forming clouds from the broadest of scales all the way down to the forming star itself. This is exciting because it may mean stars can emerge from a wider range of conditions than we once thought.”

Source & further reading:

Image: Artist impression of chaotic magnetic field lines very near a newly emerging protostar.
Credit: NRAO/AUI/NSF; D. Berry

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