Astronomers have discovered the most massive neutron star ever observed, which is close to the limit for black holes. The discovery, made using the ALMA radio telescope in Chile, suggests that the most massive stars evolve into black holes and not in another form, as was once thought.
Scientists discover the most massive
neutron star near the black hole limit
The most massive neutron stars have long been thought to be far away, far from the strong gravity of their supermassive black holes. But a team of scientists has discovered one that is much closer to the black hole limit than expected, suggesting that such stars may be more common than previously thought. The finding was made using data from the NuSTAR space telescope, which was launched in 2012 and is operated by NASA’s California Institute of Technology. It is the first time scientists have been able to observe a massive neutron star in such detail, helping them understand the physics of the phenomenon in greater detail.
Scientists find the most massive neutron star close to the black hole limit
Scientists find the most massive neutron star close to the black hole limit
According to a recent research, astronomers believe they have identified the most massive neutron star yet discovered, a pulsar that is literally near to the limit of what should be conceivable. The neutron star in question is known as PSR J0952-0607, and it is located in the Sextans constellation between 3,200 and 5,700 light years distant from Earth. This study's findings were published in the peer-reviewed academic journal The Astrophysical Journal Letters.
In the case of neutron stars and pulsars
A neutron star is essentially one of the final states of a massive star. All stars are powered by energy produced in their cores, which is created by nuclear fission fusing lighter elements to form heavier ones. This process keeps the star hot by allowing gases to expand while drawing mass toward the core in a delicate gravitational balance.
After millions or billions of years, a star, specifically one with 10-25 solar masses or more, can no longer produce this energy and collapses. As a result, a supernova blasts everything outward, while the core’s intense gravity and mass cause it to collapse in on itself, giving birth to a smaller, more compact, and more dense stellar object: a neutron star. A white dwarf star, which is similar but formed by the collapse of a much smaller star, should not be confused with this.
Despite the fact that neutron stars were once stars, they no longer produce heat because the core processes have failed. They are, of course, still hot because they need to cool down, which will take a long time. They can, however, grow in size due to accretion and collisions. The fact that neutron stars do not appear to be made of ordinary atoms is what makes them so intriguing. Rather, it appears that the collapse of the star resulted in them being entirely composed of neutrons, hence the name neutron star.
Another unique quality of neutron stars is that they still rotate.
Another distinguishing feature of neutron stars is that they continue to rotate. They spin at breakneck speeds, hundreds of times per second at times. When neutron stars rotate, they emit electromagnetic radiation beams that, if pointed in our direction, can be seen from Earth. Pulsars are neutron stars that emit these radiation jets. Because neutron stars emit little radiation, this is usually the most effective method of locating them. The Milky Way Galaxy alone is thought to contain hundreds of millions, if not billions, of neutron stars.
Scientists discover the most massive neutron star near the black hole limit
How massive is a neutron star?
Each neutron star is still only a fraction of the mass of its parent star, and they typically range from one to three solar masses. Furthermore, because of their compact nature, neutron stars are typically not very large. Rather, they may only be 20 kilometers wide. To put that in context, that's roughly the size of a city. To put it another way, there is something the size of a city with the same mass as our Sun - or up to three times the size of that.
However, that limit is significant. The Tolman-Oppenheimer-Volkoff limit states that a neutron star must be between one and three solar masses, though the exact number is unknown, and other factors, such as whether or not the star is still spinning, must be considered.
What happens if it exceeds this limit? This implies that it will continue to collapse and condense, becoming denser. A black hole could form as a result of this. Of course, this isn’t the only way black holes form or die, with some scientists hypothesizing the existence of other stars, such as quark stars, but this is still unknown.
The neutron star in question is the pulsar PSR J09520607. When it was discovered, it was already known for how fast it spun. It rotates 707 times per second, making it one of the galaxy's fastest neutron stars, according to current estimates. PSR J09520607 is notable for its size - roughly 2.35 solar masses - and the fact that it has grown even larger. This is because PSR J09520607 is classified as a "black widow." This is the name given to a neutron star that is part of a binary star system and then "eats" another star.
This isn’t entirely surprising given the discovery of binary neutron star and black widow binary star systems previously. Indeed, binary neutron stars and black widows are regarded as promising sources of neutron star growth information. The researchers had to use the sensitive Keck 1 telescope in Hawai’i to determine how much larger PSR J09520607 became as a result of devouring its stellar companion.
And the data they discovered demonstrated just how massive it is. This is significant because it adds to the understanding of what neutron stars are made of, which is a separate and very complicated topic in and of itself.
What is also intriguing about these findings is how they shed light on one of the mysteries surrounding pulsars: the spinning.
The reason neutron stars spin originally is due to the conservation of angular momentum
The conservation of angular momentum is what initially causes neutron stars to spin. That explanation, however, only goes so far as to explain when they spin once per second.What about those that spin even faster? What about pulsars, which spin hundreds or thousands of times per second and flash electromagnetic radiation beams?The only plausible explanation appears to be that something collided with the neutron star, pushing it and causing it to spin faster. But how does this happen? After all, not all pulsars are associated with a binary system.
However, one possible explanation is that these extremely fast pulsars were never alone – at least not at first. The idea is that each of these extremely fast pulsars must have had a companion star at one point, with the star’s evolution and growth influencing the pulsar and causing it to move faster. Then it is absorbed, with this new material pushing it even further, until they are all alone.
PSR J0952-0607 is still classified as a binary star because its companion is still present, albeit faintly, and has grown to be roughly 20 times the size of Jupiter, with temperatures hotter than the Sun. And, according to the researchers, this is exactly what is happening, with the black widow devouring its partner and possibly driving it to extinction, a phenomenon dubbed “cosmic ingratitude” by author Alex Filippenko of the University of California, Berkley.
The findings, however, are only a small part of the researchers’ efforts to quantify black widow pulsars and other unusual cases. The goal is to find more neutron stars on the verge of becoming black holes. If they don’t find any, it could simply mean they’ve reached their limit; anything more massive would have simply turned into a black hole.
what is a neutron star?
The universe is home to a diverse range of strange and exotic objects that appear to defy logic. There are some things in this universe that are simply bizarre. Neutron stars are perhaps the best example of how strange the universe can be. Their very existence defies our earthly logic, and they are a perfect example of something that defies our earthly logic. What is a neutron star, exactly? How do they come to be? How do they act?
what is a black hole?
A black hole is a region of space where intense gravitational fields cause objects to become infinitely dense, making it impossible for anything, including light, to escape. Despite their name, black holes aren’t actually black. They are instead defined by their mass and electromagnetic radiation such as radio, X-ray and gamma-ray light. Scientists think that some supermassive black holes may be surrounded by hot gas, called a plasma ring, which glows in X-rays when viewed from afar.
how much does a neutron star weigh
The mass of a neutron star is at least 1.1 solar masses (M). The Tolman-Oppenheimer-Volkoff limit for neutron stars is generally thought to be around 2.1 M, but a recent estimate puts the upper limit at 2.16 M.  PSR J0740+6620, discovered in September 2019, has a maximum observed mass of about 2.14 M. Compact stars with masses less than the Chandrasekhar limit of 1.39 M are generally white dwarfs, while compact stars with masses between 1.4 M and 2.16 M are expected to be neutron stars. However, the masses of low-mass neutron stars and high-mass white dwarfs can overlap by a few tenths of a solar mass.
what is a pulsar in space
Pulsars are rotating neutron stars that emit radiation pulses at very regular intervals ranging from milliseconds to seconds. Pulsars have extremely powerful magnetic fields that channel jets of particles out along their two magnetic poles. These accelerated particles produce extremely powerful light beams.
Are pulsars dead stars?
Pulsars, which are spinning dead stars made of densely packed neutrons, appear to blink on and off due to lighthouse-like radiation beams that sweep past Earth at regular intervals.
what is the average density of the sun?
The average density of the Sun is about 1.4 g/cm**3, meaning that it is about 1.4 times as dense as water. The radius of the Sun is about 1.4 million km (1,000,000 km). The mass of the Sun is 2.8 x 10**30 kg (≈3.7 x 10**33 lb). It also has other celestial bodies orbiting it, including a large moon (called the Moon), which is 150 km smaller than the Earth’s Moon and is about the same mass.
How rare is a neutron star?
During a supernova, neutron stars form and are held together by neutron degeneracy pressure. These stars are relatively rare: there are only about 108 of them in our galaxy, or one in every thousand stars, so the nearest one is most likely at least 40 light years away.