A flood of gamma rays has revealed what may be the youngest ultrafast-spinning star known. Turning up more newborn dervishes could shed light on what sets the stars spinning so fast in the first place.
Millisecond pulsars are dense stellar remannts of supernovae that spin extremely quickly, making hundreds of rotations per second. It is not clear if they are ever simply born spinning that fast or if they always take some time to ramp up to these speeds after stealing matter from a companion star
Most of the millisecond pulsars observed so far are about a billion years old, but now NASA's Fermi space telescope has confirmed that a previously identified millisecond pulsar is a mere 25 million years old ? putting it in the running for the youngest known.
Called J1823?3021A, it spins 185 times per second and is located in a star cluster 28,000 light years from Earth. The star is spinning fast but rapidly decelerating, suggesting it is very young, since otherwise its spin would have slowed to a crawl already.
To pulse or not to pulse
Pulsars slow down by converting rotational energy into radiation, and the copious gamma-rays that Fermi detected from this pulsar confirm that it is rapidly losing rotational energy, reports a team led by Paulo Friere of the Max Planck Institute for Radio Astronomy in Bonn, Germany.
"It's amazing that all of the gamma rays we see from this cluster are coming from a single object," Friere said in a statement. "It must have formed recently based on how rapidly it's emitting energy."
Only one other pulsar has an age in this ballpark, and it is not clear which is the youngest. "It's certainly one of the youngest, which makes this a very interesting system to study," says Craig Heinke of the University of Alberta in Edmonton, Canada.
It might lead to a better understanding of how millisecond pulsars form, he says. Pulsars are neutron stars that act like lighthouses, emitting beams of radiation that regularly sweep over Earth and appear to us as periodic flashes. Slow-spinning neutron stars do not emit radiation pulses, however, and the details of when and how the pulses turn on as a neutron star spins up are still not clear.
Journal reference: Science, DOI: 10.1126/science.1207141
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