UNLIKE human infants, newborn stars seem to have a way to stop themselves getting too hyper for their own good. When stars form from a spinning disc of gas and dust, they should spin ever faster as gravity pulls this matter in towards the centre 鈥� just as pirouetting ice skaters spin faster as they retract their arms 鈥� and so throw material back out. Yet for some reason this doesn鈥檛 happen.
Now researchers have shown that a young star鈥檚 magnetic field could slow the disc鈥檚 overall spin by helping to get rid of the fastest-spinning material, removing it in giant perpendicular plumes. 鈥淟ots of people have seen these jets moving rapidly away from forming stars, but we never understood why they were so well-formed,鈥� says Philip Lucas at the University of Hertfordshire. The team鈥檚 computer model suggests spiral-shaped magnetic fields are the most likely to form plumes (Nature, vol 450, p 71).
