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Post Info TOPIC: FU Orionis


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FU Orionis

The magnetic fields surrounding a young star have been detected for the first time.
This discovery confirms models of how such stars grow.
Theoretical models predict that the magnetic fields in a dusty disc surrounding a young star will slow the disc's rotation, and allow dust to fall onto the star, thus helping it to grow.

Now, researchers led by Jean-François Donati of the Observatoire Midi-Pyrénées in Toulouse, France, have observed the magnetic fields in the central regions of such a disc around a young star called FU Orionis.
They used a new high-resolution instrument called ESPaDOnS on the Canada-France-Hawaii Telescope (CFHT) in Hawaii to detect polarised light (due to the magnetic fields) from the disc.

Position(2000): RA 05 45 22.36 Dec +09 04 12.3
12'9 x 12'9

FU Orionis is a young spectral class G0 star that is still in the process of shrinking and heating up. It was first spotted (magnitude 9.5) in the sky in 1936 , before that, it was an undiscovered tiny star of 16 magnitude.

FU Orionis is 1600 light-years away and associated with a reflection nebulae in the constellation Orion.
It is located about 3 degrees NW of Betelgeuse, and less than a degree east of the small planetary nebula NGC2022.

"This is the first detection of a magnetic field in an astrophysical disc - which has been long sought after" - Jérome Bouvier of the Astrophysical Laboratory of Grenoble in France, team member.

The discovery also suggests something about the influence that magnetic fields may exert over young stars, and may explain why some stars appear to shoot out violent jets of matter while others do not.

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 have jets, and this could be because the star's magnetic fields are slowing it disc's rotation more than expected.
The effect may be due to the magnetic fields' shape and distribution – they appear to thread through only some parts of the disc rather than being distributed evenly.

"Whether or not there is a jet depends on the topology, or shape, of the magnetic field. This result will help us understand how young stars form and how circumstellar discs evolve and create outflows"- Jérome Bouvier.

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