Artist’s impression of a pulsar orbiting a black hole – one possible interpretation of the mysterious binary star system
Daniel Hutseller (artsource.nl)
Some 40,000 light-years away, a strange object could be either the heaviest neutron star or the lightest black hole ever seen, and it resides in a mysterious celestial void that astronomers have never directly observed. .
Neutron stars form when a star runs out of fuel and collapses due to gravity, creating a shock wave called a supernova and leaving behind an extremely dense core. Astrophysical calculations show that these nuclei must remain below a certain mass, about 2.2 times the mass of the Sun, or they will collapse further to form a black hole.
However, black holes have only been observed to have a mass more than five times that of the Sun, leaving a gap in scale between neutron stars and black holes. Gravitational-wave observatories have observed several dense objects in this gap, but astronomers have never discovered them with conventional telescopes.
now, Ewan Barr Researchers at Germany’s Max Planck Institute for Radio Astronomy discovered an object with 2.5 times the mass of the Sun by observing pulsars orbiting around it. A pulsar is a neutron star that emits pulses of light at regular millisecond intervals due to a strong magnetic field.
As predicted by Albert Einstein’s theory of relativity, pulsars emit light with great regularity, but very large nearby objects can distort these rhythms. Dr. Barr and his team were able to calculate the mass of the pulsar’s partner by observing the pulsar’s pulses for more than a year using his MeerKAT radio telescope in South Africa.
“What we’ve discovered in this binary system appears to go beyond that [upper limit for neutron star mass]This suggests that there is some new physics going on here and that this is either a new type of star, or simply a black hole, the lightest stellar-mass black hole yet discovered. “There will be,” Barr said.
Pulsars are located in globular clusters, which are dense regions of stars and some rare objects that can pass close to each other. These unusual interactions could explain the mysterious object, Barr said.
If it’s a black hole, researchers will be able to test theories of gravity that weren’t possible before. “A pulsar is just a ridiculously accurate measuring device in orbit around a black hole, but it’s not going anywhere. It’s going to be around for the next billion years,” Barr says. “So this is an incredibly stable and natural test bed for investigating the physics of black holes.”
“If it’s a neutron star, it would be more massive than any neutron star we’ve ever seen,” he says. Christine Dunn At Durham University, UK. “This actually tells us about the ultimate density a star can support before it collapses under its own gravity and becomes a black hole. I don’t know what the limits are.”
Barr and his team plan to observe the pulsar with other telescopes over the next few years, looking for clues about what the object is. If it was a black hole, we would see the pulsar’s orbit change over time, as the black hole dragged through spacetime around it, much like a ship dragging a small boat behind it. Or if it’s a neutron star, more sensitive instruments might be able to detect the light.
topic:
