Astronomy is full of mysterious objects, but an international research team has added another interesting one. It is a dense, compact object that orbits a pulsar. While this is not groundbreaking in itself, the mass of this object is puzzling. It is located in the so-called mass gap. Researchers are observing either the heaviest neutron star or the lightest black hole known.
When a star much more massive than the Sun goes supernova, two different types of objects can form. If it’s not too big, it will collapse and become a neutron star. Neutron stars are stars made entirely of neutrons (zero-charged particles at the center of atoms) and have an incredible density. A teaspoon of neutron star material weighs as much as a mountain.
Neutron stars have various properties. A pulsar is a type of neutron star that rotates around its axis at high speed and emits periodic pulsations. Millisecond pulsars, like the object in this study (called PSR J0514−4002E), rotate hundreds of times per second. They work like the most accurate clocks in the universe.
Another dense object created by a supernova is a black hole. This is a celestial object so dense that not even light can escape. Observations and theory estimate that the heaviest possible neutron star is 2.2 times the mass of the Sun. The lightest black hole is expected to have a mass about five times that of the Sun. There is a mass gap in between, and unless something is missing in the physics of neutron stars, we would expect the object to be a black hole.
In this case, the pulsar’s companion star has a mass between 2.09 and 2.71 times that of the Sun. It could be a system with pulsars and black holes. Or there are neutron stars, one of which is pulsating.
“Both possibilities about the nature of the companion are interesting. Pulsar-black hole systems are important targets for testing theories of gravity, and heavy neutron stars offer new insights into very dense nuclear physics. co-author Professor Ben Stappers from the University of Manchester said in the paper. statement.
The pulsar rotates (and therefore pulsates) 170 times per second, as observed by the MeerKAT radio observatory. By studying small changes in this rhythmic signal, the researchers were able to deduce the properties of the system. The precision achieved is incredible considering that these two celestial bodies are 40,000 light years away.
“Think of it like taking a near-perfect stopwatch and being able to drop it into orbit around a star about 40,000 light-years away and time that orbit with microsecond precision,” Max said.・Ewan Bahr of the Planck Institute for Radio Astronomy added: Researched with his colleague Arunima Dutta.
The researchers believe that this companion star was not a direct result of a supernova, but was originally two neutron stars that merged into this massive object.
It may seem strange to have three neutron stars in one system, but this object is located in a globular cluster. This is a spherical collection of stars with a much higher density than other places in the galaxy, like our neighborhood. It is common for many stars to interact within globular clusters. Such interactions likely led to the formation of incredible objects. We still don’t know exactly what it is, but researchers are working hard to find out.
“This system is not finished yet,” Arunima Dtta concluded. “When I uncover the true identity of my friends, [be] It’s a turning point in our understanding of neutron stars, black holes, and what else may be lurking in the mass gaps of black holes. ”
A paper describing this research has been published in the journal science.