Making Starbirth Easier

Outcome: A new model of star formation which uses the advances in understanding of magnetic reconnection has been tested with numerical simulations.

Transformative: The traditional paradigm of star formation based on ambipolar diffusion process faces severe problems explaining observational data. New model can explain new observations and opens ways to better modeling star formation.

Explanation.

Scientific problem: All stars including our Sun were born from clouds of gas as gravitational forces collected the matter from the scales of light years into relatively small dense hot luminous objects. Gas from which stars are born exhibits chaotic turbulent motion and it carries magnetic fields that counteract the gravitational collapse. For years the problem of removing of magnetic field from star forming regions has the focus of intense studies by astrophysicists. Magnetic fields couple with the gas in molecular clouds through their interactions with the minute fraction of ions present in the gas and, traditionally, it is assumed that the slippage of the ions and gas atoms, which is called ambipolar diffusion is responsible for the loss of magnetic field.

Breakthrough: The paper challenges the above accepted paradigm and identifies a process of  magnetic reconnection in turbulent media as the major process of magnetic field removal from collapsing molecular clouds. This finding is based on the model of turbulent reconnection by Lazarian & Vishniac 1999. Simulations within the paper exhibit fast removal of magnetic flux without ambipolar diffusion.

Significance: Star formation is one of the most fundamental problems of astrophysics with large interest of general public. Simulations in the paper explain the observational data that cannot be explained with the existing paradigm of ambipolar diffusion.

International collaboration: This work is a result of international collaboration. A student from Brazil came to Madison to work with the PI to test numerically the PI’s idea of new scenario of star formation.