Oct 27, 2014

Baby Stars' Twisted Magnetism More Chaotic Than Thought

As we zoom-in to stars light-years distant, we’re not only trying to understand the vast stellar menagerie that awaits our telescopic inquisitiveness, we’re also trying to decipher where we — and our bountiful solar system — came from.

Interestingly, the answer to how our unique planetary system came into being may be hiding in the magnetic configuration of a young sun that sparked to life over 4 billion years ago. Now, astronomers appear to have added another interesting finding to the magnetism surrounding a young star and how that may influence its ability at building a system of planets — thereby providing an insight to how our primordial solar system came to be.

Stars form as large clouds of cold molecular gas collapse under mutual gravity, eventually creating an environment so dense that nuclear fusion can spark inside stellar cores. Surrounding these embryonic stars, disks of gas and dust collect, creating accretion disks. It’s from these accretion disks that planetary systems will eventually evolve.

However, a baby star’s emerging magnetic field is thought to have a huge impact on planetary formation and the magnetic field’s configuration can make a huge difference for the final outcome of that star system.

Until now observations of young stars’ magnetic fields have been hard to come by, but an international team of astronomers have now measured the magnetic field surrounding a T Tauri star only 1 million years old. Their research was published in the journal Nature last week.

T Tauris are stars that are currently undergoing gravitational contraction and it is thought that the magnetic field these T Tauri stars possess strongly influence the configuration of the stars’ accretion disks. Using the Combined Array for Research in Millimeter-wave Astronomy (CARMA) of radio telescopes in California, the researchers were able to capture the magnetic morphology of the T Tauri star HL Tau, which is located 450 light-years from Earth

Theoretical studies of baby star magnetic fields suggest they should either be “poloidal” (magnetic field lines that loop from the north to south poles of the protostar) or “toroidal” (wrapped around the circular accretion disk). What the observations of HL Tau appear to show, however, is a more complex picture — neither theoretical model fits the observation.

Read more at Discovery News

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