Magnetic Fields in the Process of Star Formation

A controversial issue for astronomers has been the role that magnetic fields play in the process of star formation. Magnetic fields permeate the galaxy, and astronomers have long thought that dust grains can move along field lines during the collapse process. The traditional view is that the magnetic field should follow the collapsing material and resulting outflow, forming an hourglass shape with the protostar at the center. However, the details of this process have remained a mystery.

Dr. Chat Hull gave a lecture at NAOC on August 13, 2014, addressing this topic. Dr. Hull's work has involved observing how magnetic field lines are oriented in collapsing clouds of material that will later form stars. He has considered this problem on many scales, from a parsec to 100 AU. By analyzing data taking with projects like CARMA and TADPOL, he has compared the magnitude and direction of magnetic field lines with the direction of flows in clouds. Surprisingly, his conclusions, as well as the conclusions of a number of other researchers in this field, showed that the magnetic field was either randomly oriented with respect to the collapsing material, or perpendicular to it. He went on to explain that these two situations can be understood by considering interactions with the ambient magnetic field, and whether or not the magnetic field becomes entangled in the collapsing material. Dr. Hull also explained that future observations with ALMA will have better resolution, allowing an even more detailed analysis of how magnetic fields interact with flows of materials. Moreover, ALMA will allow more targets to be observed, expanding the number of cases that can be analyzed.

 

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