A mysterious dark object in space sparks research

Is it the heaviest neutron star, the lightest black hole, or something else entirely? A mysterious object in space baffles researchers.

Bonn – An international research team led by Ioan Parr and Arunima Dutta (Max Planck Institute for Radio Astronomy in Bonn) has discovered a mysterious and dark object in space. Its mass is 2.35 times the mass of our Sun, which is heavier than the heaviest known neutron stars and at the same time lighter than the lightest black hole known to date. This is unusual – the mass lies precisely in the so-called mass gap between neutron stars and black holes.

When a massive star dies, its interior collapses, creating a neutron star or black hole. According to current theory, a neutron star cannot contain more than 2.2 times the mass of the Sun. Otherwise, the neutron star would become a black hole whose gravity would not allow even light to escape. However, black holes in the universe are known to be only about five solar masses in size, a mass gap that objects have not yet filled.

Discovery of a mysterious dark object in space

Is it a particularly light black hole or a particularly massive neutron star? The research team has not yet found a specific answer to this question. In a guest post On the gate Conversation However, the team explains why this object is so exciting: “If we want to understand the physics at the boundaries between neutron stars and black holes, we have to find objects at these boundaries.” The study in which the research team announced its discovery for the first time In the specialized magazine Sciences published.

The research team discovered the mysterious and dark celestial body in the spherical star cluster NGC 1851 in the southern constellation Columba (the Dove). The group observed a globular cluster pulsar, a type of neutron star that rotates very quickly and sends radio signals out into the universe. The newly discovered pulsar PSR J0514-4002E rotates on its axis more than 170 times per second, with each rotation producing a pulsation similar to the ticking of a clock. By measuring this “ticking,” researchers can precisely determine the pulsar’s orbital motion.

Neutron star or black hole? The research is inconclusive

“Imagine being able to put a nearly perfect stopwatch into the orbit of a star about 40,000 light-years away, and then measure the time of the orbits to microsecond precision,” says Barr, describing so-called pulsar timing. When measuring the newly discovered pulsar, the research team discovered that the celestial body revolves around an invisible body. The group was also able to determine the mass of the mysterious object.

“Whatever this object is, it is exciting news,” co-author Paulo Freire says in one article. notice From the Max Planck Institute. “If it is a black hole, it is the first known system of pulsar black holes, the discovery of which has been the holy grail of pulsar astronomy for decades!” On the other hand, if it were a neutron star, it would have “fundamental implications for understanding the unknown state of matter at these amazing densities,” the researcher continued.

An unknown object is located in a tight, dense spherical mass

The research team has a preliminary theory about how the massive, mysterious object formed: the dark object and the pulsar are located in a very close environment in the globular cluster. Due to the small distance between them, stars can disrupt each other's orbits and even collide with each other. It is possible that the newly discovered object arose from such an impact. “This is the most unusual binary pulsar discovered to date,” confirms co-author Thomas Torres (Aalborg University). “Its long and complex origin story pushes the boundaries of our imagination.”

Whether the mysterious object is a more massive neutron star, a lighter black hole, or something else entirely, it is sure to be studied further in the future. “We are not done with this system yet,” says Arunima Dutta. “Revealing the true nature of the companion will be a turning point in our understanding of neutron stars, black holes, and whatever else might be lurking in the black hole’s mass gap.” (unpaid bill)