Magnetic fields and turbulence fight against gravity by channeling gas flows and stirring things up, respectively, according to a press release. New information on magnetic fields indicates they affect star formation from hundreds of light-years down to a fraction of a single light-year.
The new study will be published online in the journal Nature on March 30.
Cat's Paw Nebula, or NGC 6334, was observed. The nebula holds about 200,000 suns' worth of material that is churning and ready to form stars - some with 30 to 40 times the mass of our sun. The nebula is located 5,500 light-years away from Earth in the constellation Scorpius.
"We found that the magnetic field direction is quite well preserved from large to small scales, implying that self-gravity and cloud turbulence are not able to significantly alter the field direction," said lead author Hua-bai Li from The Chinese University of Hong Kong, who conducted the resolution observations while a post-doctoral fellow at the Harvard-Smithsonian Center for Astrophysics (CfA), according to the press release.
"Even though they're much weaker than Earth's magnetic field, these cosmic magnetic fields have an important effect in regulating how stars form," added Smithsonian co-author T.K. Sridharan from CfA, according to the press release.
Several facilities were used to polarize the light coming from the nebula, including the Smithsonian's Submillimeter Array. "The SMA's unique capability to measure polarization at high angular resolution allowed access to the magnetic fields at the smallest spatial scales," said SMA director Ray Blundell from CfA, according to the press release.
"The SMA has made significant contributions in this field which continues with this work," said Smithsonian co-author Qizhou Zhang from CfA, according to the press release.
Since dust grains align with magnetic fields, the scientists were able to use dust emissions as a measurement of the field's geometry. "They found that the magnetic fields tended to line up in the same direction, even though the relative size scales they examined were different by orders of magnitude," according to the press release. "The magnetic fields only became misaligned on the smallest scales in cases where strong feedback from newly formed stars created other motions.
When a cloud collapses and forms stars, magnetic fields get in the way, so only a fraction of the material becomes stars. The material that is left over gets dispelled into space, so magnetic fields keep the pace of star formation.
From the press release:
"Headquartered in Cambridge, Mass., the Harvard-Smithsonian Center for Astrophysics (CfA) is a joint collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory. CfA scientists, organized into six research divisions, study the origin, evolution and ultimate fate of the universe."