Astronomers have captured the first image of a strange, S-shaped jet erupting from a neutron star, and the bizarre emission suggests the dead star resembles the water spurting from a garden sprinkler.
Neutron stars use their companion stars as food Space Vampire A high-energy jet spews out from it, forming an S-shape as the dead vampire star wobbles and “precesses” like a top, and the team hopes that this first observation will help improve understanding of the phenomenon. Extreme physics around neutron stars It’s something you won’t find anywhere else in the universe.
The S-shaped jet was discovered by astronomers from the University of Oxford using the MeerKAT radio telescope in South Africa, and the data they collected was used to create the most detailed, high-resolution images of Circinus X-1 to date.
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“This image is the first time we’ve seen such strong evidence of a confirmed precessing jet from the lunar surface. Neutron Star “Evidence for this comes from both the symmetric S-shape of the radio-emitting plasma within the jet, and the fast, wide shock waves that can only be produced by the redirection of the jet,” team leader Fraser Cowie, a researcher at the University of Oxford, said in a statement.
“This will yield valuable information about the extreme physics behind jet launches, a phenomenon that is still poorly understood.”
Cowie3 Moving Shock Cir X 1 – YouTube
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Why does this neutron star act like a garden sprinkler?
Neutron stars are Massive stars run out of hydrogen The fuel needed for nuclear fusion is produced in the core, eliminating the outward pressure of energy (in the form of radiation pressure) that would support the star against the inward pressure of its gravity. After this billion-year struggle, gravity inevitably wins, and the outer layers of the star melt. Dying Star It will be blown away in a giant supernova explosion.
Meanwhile, the core would collapse gravitationally, squashing the mass of one or two suns into a mass about 12 miles (20 kilometers) wide. The result would be a newborn neutron star large enough to fit within the boundaries of a standard Earth city, but so dense that just a tablespoon of its material would weigh more than a billion tonnes.
Furthermore, not all neutron stars exist alone. A binary star system with a companion star. And if these stars are close enough to each other, the neutron star could act as a kind of cosmic vampire, stripping stellar material from its companion, or “donor,” star.
An illustration of a neutron star compared to Manhattan Island. (Image courtesy of NASA Goddard Space Flight Center)
But the material stripped from the donor star still has angular momentum, so it cannot fall directly into the neutron star: instead, it forms a flat cloud around the dead star, which gradually feeds the neutron star. Accretion disk.
The incredible density of a neutron star means that when this stolen material hits its surface, an enormous amount of energy is released. In just one second, a neutron star can release the same amount of energy. Sun It will be released over a period of 1 million years.
Some of this energy is funneled into jets of material that erupt from the neutron star at speeds equal to a significant fraction of the speed of light.
An image of the Circinus X-1 neutron star showing how the eruption progressed, culminating in the ejection of an S-shaped jet. (Image courtesy of Fraser Cowie)
observation Circinus X-1 A 2007 survey showed that the system is particularly bright in X-rays and is usually Black Hole System This was the first time that this type of jet had been observed erupting from a neutron star system, showing similarities to a black hole.
This makes Circinus X-1 an unusual system that defies traditional classifications, making it of great interest to astronomers who will use it to test their knowledge about the accretion process, the jet itself, and also the jet’s interaction with the surrounding material.
So the new research team recently upgraded MeerKAT Radio Telescope The researchers deployed instruments on Circunus X-1 in the hope that their sensitivity would provide more information about this fascinating system, and they obtained high-resolution images that showed clear evidence of an S-shaped structure in Circunus X-1’s jet.
The team believes that these jets have an unusual shape because their source neutron stars “wobble” like a top as they begin to slow down. “The wide angle propagation of these shock waves is consistent with our model,” Cowie says. “This means we have two strong pieces of evidence that neutron star jets are precessing.”
Cowie et al.Ending Shock “They occur when neutron star jets collide, sending ripples through the surrounding material. This is the first time such observations have been made in such a binary system.”
However, the conclusive evidence that the shock wave is generated by a jet is the fact that its speed is about 10% of the speed of light. This extremely high speed must be due to such a high energy jet. The shock wave actually acts as a “cosmic particle accelerator” and generates a stream of high energy particles called “cosmic rays”.
Further investigation into the speed of the shock wave may shed light on what the jet that generated it is made of.
“Circinus X-1 is one of the most luminous objects in the X-ray galaxy and has been studied for over half a century,” said Cowie, “but despite this, it remains one of the most mysterious objects we know. Several aspects of Circinus X-1’s behavior remain poorly explained, so it’s extremely rewarding to be able to build on 50 years of work by others and help shed new light on this object.”
The team’s next step is to monitor the jet to determine whether it’s changing over time as expected, or whether the system holds any additional surprises. “This will allow us to measure the jet’s properties more precisely and learn more about this mysterious object,” Cowie said.
These results were published by the Royal Astronomical Society 2024 National Astronomy Conference It takes place at the University of Hull on Monday (16 July).
