The dead strange magnetar star has a solid surface, which surprises astronomers

Neutron stars are some of them The most extreme phenomena in the entire universeNew discoveries about these dense stellar bodies continue to surprise scientists. Recently, astronomers announced the discovery of a magnetized neutron star that appears to have all its own Solid Surface. Stars are usually made of hot celestial bodies of plasma, a type of ionized gas. Whereas neutron stars, due to their incredible density, are usually ripples of extremely compact solid matter (mostly neutrons) with a core that is a type of frictionless fluid called a superfluid. It often has an atmosphere, like Earth too. The idea of ​​a completely solid neutron star, resembling a very dense planet with no atmosphere, is very unique.

Writing reports in the magazine SciencesAn international team of 50 researchers used data from the X-ray Imaging Polarimetry Explorer (IXPE), a satellite launched by NASA and the Italian space agency in December 2021. The astronomers pulled information on the indirectly named neutron star 4U 0142+61. It’s a special kind. A neutron star, called a magnetar, is located about 13,000 light-years from Earth in the constellation Cassiopeia.

A magnetar is basically what it sounds like: a neutron star with a very strong magnetic field. There are only about 30 that we know of, probably because they are so hard to find. They’re small and faint, and can only be detected during periods of enhanced activity, such as when enough high-energy electromagnetic radiation (think gamma rays or X-rays) explodes that they’re hard to detect on Earth.

4U 0142 + 61 CAN first discovery in the 1970s by a NASA satellite called Uhuru, named after the Swahili word for “freedom”. It is the first instrument ever launched to detect X-rays in space, which cannot be seen with the naked eye. In fact, the quirky jumble of letters that make up this star’s name comes from 4U of the “Fourth Uhuru Catalog,” while the numbers refer to the celestial coordinates of the magnetar.

A typical neutron star has more mass than our Sun, but its radius is only twelve kilometers.

But even though this star was discovered decades ago, there was little data on it before IXPE appeared. With this new X-ray meter, astronomers can calculate a star’s polarization, which means the direction and angle through which its electromagnetic waves are moving. This can provide information about the physical conditions and processes that form a star and marks the first time that polarized X-ray light has been captured from a magnetar.

Some stars, when they die, become neutron stars. (Stars whose mass is greater than the threshold become neutron stars black holes When it collapses.) When large stars begin to form heavy elements through the process of nuclear fusion, the force of their gravity causes the star to begin to collapse in on itself. This force is so strong that it fuses the electrons and protons in the nucleus of an atom together, forming neutrons, creating a dense material like the atomic nucleus. A typical neutron star has more mass than our Sun, but its radius is only twelve kilometers; Thus, one tablespoon of neutron star matter weighs 1 billion tons. This intense density, a very tightly packed soup of neutrons, causes neutrons to behave like a solid or a superfluid—even though they’re made up of subatomic particles, they’re not technically atoms. Neutron stars also attract more diurnal (atomic) matter by virtue of their gravity, and often have atmospheres similar to planets.


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But things turn out much differently for 4U 0142+61, which astronomers believe has a violent history, even for a neutron star. Actually he Solid, or so it seems. About 100,000 years ago, the star went supernova, which means it exploded and ejected most of its mass, enough to contain about a dozen of Earth’s planets. This is amazing A dirty tablet is formed from the substancethe first disk ever discovered, orbits 4U 0142+61 at about a million miles (1.6 kilometers) away.

“It was completely unexpected. I was convinced there would be an atmosphere.”

However, the surface of 4U 0142+61 may be more interesting than the goo around it. The Science researchers report, based on the new data from IXPE, that it is very unlikely that the energy coming from 4U is “compatible with the presence of an atmosphere and only marginally compatible with a condensed surface.” This hard shell, most likely made of iron, would distort the structure of the atoms so that they would no longer be spherical but rather flattened and extended in the direction of the magnetic field. This will form a network of ions bound together by these magnetic forces. In other words, the surface may not be made of neutrons but of “normal” matter, such as what makes up the Earth – in this case, iron.

One of the study’s lead authors, Professor Silvia Zen, member of the IXPE science team, said: statment. There may be an alternative explanation here, but as of now, there is insufficient data to explore these other possibilities. “The next step is to observe hotter neutron stars with a similar magnetic field, to investigate how the interaction between temperature and magnetic field affects the star’s surface properties.”

There are other strange solid stars called white dwarfs, but this matter is still very different from solid matter on Earth. White dwarfs are the remnants of stars that have used up all of their nuclear fuel and collapsed in on themselves due to their gravity. This presses its core, which is composed of solid oxygen and carbon, in superheated crystals. Because white dwarf stars no longer produce any energy, they slowly radiate thermal energy in the form of photons. After trillions of years, the white dwarf will eventually become a solid, cold mass of matter, like a very dense planet. However, astrophysicists calculate that this type of star, known as a black dwarf, will take so long to cool down that there are still no black dwarf stars anywhere in the entire universe. Earth’s sun will eventually end its life as a white dwarf and then a black dwarf. Stars in general are strange phenomena, but those with solid properties take physics to strange extremes.

IXPE is an exciting new astronomy tool that hasn’t garnered as much attention as, for example, James Webb Space Telescope. But IXPE has also helped scientists determine the composition of the hot matter surrounding a black hole called Cygnus X-1 And helped solve 40 years The secret of how blazars work. Blazars are some of the brightest objects in the universe, spewing jets of ionized matter that travel at almost the speed of light. There are some strange things out there in the universe and 4U 0142+61 is just one of the many mysterious stars that offer so much to discover.

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