Peplo soup, Nature (translation: Dikla Oren)
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Astronomers realized that a structure of two stars is actually a pair of pulsars. This unique discovery will allow them to examine Einstein's theory of general relativity in new ways and to reach a better understanding of the bursts of energy that pulsars produce.
"This is a discovery of enormous importance," says Robert Masai of the Royal Observatory in Greenwich, London, UK. Einstein predicted the existence of gravitational waves, but these were never directly observed. "There aren't many objects out there that might be an abundant source of gravitational waves, but this is definitely one of them," he says.
An international team of scientists published information about the binary system in December, but at the time they thought it contained one pulsar and a neutron star, which is an interesting combination in itself. Pulsars - spinning stars that emit beams of light and radiation - are sometimes called "the lighthouses of the universe". Neutron stars are the terrifyingly dense remnants of a star that exploded in a supernova. The discovery that the small neutron star is also a pulsar makes the system even more unique.
The initial mistake is simply a matter of bad luck, says Andrew Lynn, director of the Jordal Bank Observatory in Macclesfield, UK, and lead author of the paper on the initial research. As the two pulsars orbit each other, the larger pulsar disrupts the homomagnetic field of its twin brother and causes the radiation beam to be distorted. "We looked at each part of the sky for a total of four minutes. It's a matter of luck that the first time we looked at the system, the small pulsar was too faint to be seen," Lin says.
While the large pulsar rotates every 23 milliseconds, its companion completes one rotation every 2.8 seconds – slightly slower than a record on a record.
Lin and his colleagues estimate that the system was created by the large pulsar, which sucked material from a nearby star and began to rotate faster and faster. After that, the second star exploded in a supernova and became another, smaller pulsar.
It is estimated that double stars such as these emit gravitational waves, as the stars revolve around each other and lose energy, until they meet in a huge collision. The end of the pulsar dance of death is expected to come in eighty-five million years, and it will be accompanied by one last huge burst of gravitational waves.
Four other phenomena, which classical Newtonian mechanics do not explain, had already been measured in the binary system, and were consistent with Einstein's theory of gravity.
The orientation of the two pulsars means that the radiation emanating from one of them shines through the magnetic field of the other. This is an unprecedented opportunity, giving scientists the opportunity to study what is happening right next to a pulsar. "In the past all we could do was make guesses about things like this," Lin says. "Now we can actually watch them."
Link to the original article in Nature
Yadan Astrophysics 2 - stars and galaxies
https://www.hayadan.org.il/BuildaGate4/general2/data_card.php?Cat=~~~736795444~~~97&SiteName=hayadan
