Jets shoot from Centaurus A in this X-ray image. Recreating jets in the lab should help astronomers understand how these powerful jets form. Movies of the recreated jets can be seen here.
Credit: NASA
TURIN: It’s not always easy to recreate the heart of a star, but a team of Italian and US researchers have made lab equipment that recreates the jets that shoot out of stars and black holes.
Astrophysical jets are narrow streams of charged particles spurting from the centre of young stars and supermassive black holes. They hurtle in opposite directions at near light speed and extend several hundred thousand light years into space.
Previously astronomers used computer simulations to understand the jets, which they believed were linked to magnetic fields around stars and black holes.
Now, in a slim cylindrical vessel measuring four metres long and half a metre wide at the Technical University of Turin, Italy, the international team has recreated space-like conditions to observe the behaviour of astrophysical jets in the laboratory, they report in a recent issue of the New Journal of Physics.
In a surprising twist they found that the lab jets mimicked astrophysical jets, but without the magnets astronomers believed were intrinsic to their formation in nature.
How to make jets
Astrophysics in the laboratory is "rather more economical than space-based telescope observations" and is a new and growing field, said lead author and aeronautical engineer Daniela Tordella, from the Technical University of Turin.
By compressing and pumping helium, argon, xenon and normal air, Tordella's team were able to propel the gases into the vessel's vacuum via a specialised nozzle with a velocity of 4828km/s.
At the far end of the container, a sheet of electrons intercepted the flows, which caused a section of the jet to become fluorescent. A fast camera equipped with an image intensifier captured the beam, allowing the group to observe, first hand, the properties and evolution of astrophysical jets.
The observations, combined with 3D computer simulations, showed that, contrary to previous ideas, magnetic fields do not need to be present to recreate the observed properties of real life astrophysical jets.
Look, no magnets
The generated jets maintained their narrow structure without the application of a magnetic field, the researchers pointed out.
"On purpose, we did not include the magnetic field in the experiment, to see how much of the physics can be described under the Newtonian model," said Tordella. "The answer is that, on the contrary to what is believed, the extreme collimation and many aspects of the overall morphology are reproduced."
