For the first time, astronomers have discovered a neutron star with redirecting jets. The jets, which have been likened to garden sprinklers, come from an extraordinary object. Circinus X-1is one of the brightest and best-studied objects in the X-ray sky, but it turns out there’s still a lot to discover about it.
Circinus X-1 is a binary star system. It consists of a neutron star, the extremely dense remnant of a star that has exploded as a supernova, orbiting a companion star and stealing material from it. Some of that material is pushed out of the binary system in the form of powerful jets. These jets are typically Found around black holes However, the first neutron star to be observed to have a jet was Circinus X-1, in 2007. Interestingly, it has now been observed that the jet does not travel in a straight line.
Circinus X-1 is a very well-studied object in our field, but even after 50 years of study it still remains a mystery.
Fraser Cowie
The interaction of the spinning star with the disk of material causes precession, which changes the direction of the neutron star’s rotation and the point of the jet, just as a top slows down. This motion makes the jet look like a garden sprinkler or a gymnast’s ribbon.
“[The research] teeth “It’s really exciting because Circinus X-1 is a source that is very well studied in our field, but even after 50 years of people studying it, it still remains a mystery.” Fraser CowieResearchers from Oxford University who published the new study told IFLScience: “Now, with our new observations, we can shed a bit more light on why this is puzzling and see many more features. We’re starting to tie together different puzzling things to paint a more unified picture.”
Radio image of an S-shaped precessing jet emanating from the Circinus X-1 neutron star.
Image credit: Fraser Cowie
The observation is MeerKAT Telescope South Africa. Recent upgrades that increase the sensitivity and resolution of radio observations have allowed researchers to see more detail into Circinus X-1’s jet, discovering its S-shaped structure.
The accretion of material into neutron stars is an extremely energetic process. Neutron stars are so dense that a teaspoon of material weighs as much as Mount Everest. When material falls into these extremely dense objects, it releases the energy of one million suns per second. Some of that energy propels some of the falling material into jets.
The jet is traveling at a speed close to the speed of light. It slams into the material surrounding the binary system, creating a termination shock wave. The jet is traveling so fast that it interacts with interstellar material, creating a shock wave.
These termination shocks are traveling at 10 percent of the speed of light, so they must be caused by jets; even the winds from neutron stars are not that energetic. This is the first time a moving termination shock has been observed around an X-ray binary.
“We’re still continuing to make observations with MeerKAT every week, which allows us to do two things: we can stack all the images together and look for new, even fainter structures, or we can look at how the source is changing over time,” Cowie told IFLScience about the current research. Circinus X-1 will be tracked at multiple wavelengths, which will give us a more comprehensive picture of the system.
This study National Astronomical Congress July 15, 2024.
