Crab Nebula shoots off surprising flares

WASHINGTON - Scientists have discovered that the Crab Nebula, one of our best-known and most stable neighbours in the winter sky, has a propensity for fireworks-gamma-ray flares set off by the most energetic particles ever traced to a specific astronomical object.

The discovery is leading researchers to rethink their ideas of how cosmic particles are accelerated.

“We were dumbfounded,” said Roger Blandford, who directs the Kavli Institute for Particle Astrophysics and Cosmology, jointly located at the Department of Energy’s SLAC National Accelerator Laboratory and Stanford University.

Also known as M1, the Crab Nebula was the first astronomical object catalogued in 1771 by Charles Messier.

“It’s a big deal historically, and we’re making an amazing discovery about it,” said Blandford.

Blandford was part of a KIPAC team led by scientists Rolf Buehler and Stefan Funk that used observations from the Large Area Telescope, one of two primary instruments aboard NASA’s Fermi Gamma-ray Space Telescope, to confirm one flare and discover another.

The Crab Nebula, and the rapidly spinning neutron star that powers it, are the remnants of a supernova explosion documented by Chinese and Middle Eastern astronomers in 1054.

After shedding much of its outer gases and dust, the dying star collapsed into a pulsar, a super-dense, rapidly spinning ball of neutrons that emits a pulse of radiation every 33 milliseconds, like clockwork.

Though it’s only 10 miles across, the amount of energy the pulsar releases is enormous, lighting up the Crab Nebula until it shines 75,000 times more brightly than the Sun. Most of this energy is contained in a particle wind of energetic electrons and positrons traveling close to the speed of light.

The findings were reported in the Science Express.(ANI)