Astronomers have detected the magnetic fields surrounding a young star for the first time, confirming models of how such stars grow.
Based on the theory that the process differs from star to star, the observations could help explain why some stars appear to shoot out violent jets of matter while others do not.
Theoretical models predict that the magnetic fields in a dusty disc surrounding a young star will slow the disc鈥檚 rotation, allowing dust to fall onto the star, thus helping it to grow. However, researchers had never actually observed the magnetic fields in the central regions of such a disc.
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Now, researchers led by Jean-Fran莽ois Donati of the Observatoire Midi-Pyr茅n茅es in Toulouse, France, have observed these fields in a bright disc called FU Orionis that surrounds a young star. They used a new high-resolution instrument called ESPaDOnS on the Canada-France-Hawaii Telescope (CFHT) in Hawaii to detect light from the disc that was polarised by the influence of the disc鈥檚 magnetic fields.
Funnelled outwards
鈥淭his is the first detection of a magnetic field in an astrophysical disc 鈥� which has been long sought after,鈥� says team member J茅rome Bouvier of the Astrophysical Laboratory of Grenoble in France.
The discovery also suggests something about the influence that magnetic fields may exert over young stars.
Bouvier notes that many young stars shoot out jets of material from their poles, supposedly because the magnetic fields in and around them funnel material outwards. But this young star does not boast jets, and this could be because the star鈥檚 magnetic fields are slowing it disc鈥檚 rotation more than expected. The effect may be due to the magnetic fields鈥� shape and distribution 鈥� they appear to thread through only some parts of the disc rather than being distributed evenly.
鈥淲hether or not there is a jet depends on the topology, or shape, of the magnetic field,鈥� Bouvier told New 杏吧原创. 鈥淭his result will help us understand how young stars form and how circumstellar discs evolve and create outflows.鈥�
Journal reference: Nature (vol 438, p 466)
