Astrophysicists say neutron stars are essentially giant cosmic pralines

Illustration of two giant pralines in space.

Illustration showing the inner workings of heavier (left) and lighter (right) neutron stars, visualized as candy.
Clarification: Peter Kiefer and Luciano Rizzola

Astrophysicists modeling the interiors of neutron stars have found that highly compact objects have different internal structures, depending on its mass. that they Suggest Thinking of the stars As different types of chocolate fudge are, they’re delicious—but that’s where the similarities end, at least as far as we know.

Neutron stars are The extremely dense bodies of massive stars that exploded; They are second only to black holes in terms of their density. Neutron stars are so named because the force of their gravity causes their atoms to electrons to collapse on protons, creating an object made up almost entirely of neutrons.

The gravitational fields of neutron stars are extreme capacitor. If a human observer approaches one, so will it Torn on an atomic level. they gravitational fields Very strong That “mountain” stands on a neutron star less than a millimeter in length.

The latest research team has built millions of models to try to do just that Distinguish the inner workings of these stars that are remarkably difficult to study, as a result of, It is the field of theory more than observation.

The researchers found that the lightest neutron stars – those about 1.7 times the mass of our sun and below –He must have a soft mantle and a hard heart. Heavier neutron stars have the opposite, according to the team’s results, which they were published Today in The Astrophysical Journal Letters.

Luciano Rezzolla, an astrophysicist at the Institute of Theoretical Physics and who led the research, likened the stars’ structure to chocolate pralines.

“Light stars resemble those chocolates that have a hazelnut in their centre surrounded by soft chocolate, whereas heavy stars can be considered more like those chocolates where a hard layer contains a soft filling,” Rezzolla said in a Goethe University Frankfurt release.

Researchers have modeled more than a million possible neutron star formation scenarios. Based on predictions of the star’s mass, pressure, size, and temperature, as well as astronomical observations of the objects.

Modeling is an essential way to interrogate neutron starsBecause there are very few contraceptives on Earth–The Large Hadron Collider of the European Organization for Nuclear Research (CERN) And the SLAC issue in extreme conditions A tool for two – capable of simulating such intense physics.

To determine the stars’ symmetry, the researchers modeled how the speed of sound travels through objects. Sound waves are also used to understand the internal structure of planets, such as Undaunted, InSight did it on Mars.

Illustration showing possible layer formation of a neutron star.

“What we have shown, by building millions of equations of state models (from which the speed of sound can be calculated), is that neutron stars with maximum mass have a lower speed of sound in the core region than in their outer layers,” said Christian Ecker. , an astrophysicist at Goethe University, in an email to Gizmodo.

“This hints at some physical changes in the nuclei, such as the transition from baryonic matter to quark matter,” Ecker added.

The researchers also found that all of the neutron stars are probably about 7.46 miles (12 km), regardless of its mass. This measurement is less than half that of A 2020 find A typical neutron star would have been about 13.6 miles (22 km) across. Despite this size, the average mass of a neutron star is present Half a million lands. There is dense, then there is Dense.

While the results offer some insight into the diversity of neutron stars in terms of their symmetry, the researchers did not look at what the stars are made of or how they fit together. (If you got that far, neutron stars aren’t actually made of chocolate.) Some doubt that neutron stars are neutrons all the way; Others believe that the centers of the stars Factories of exotic particles that have not yet been identified.

But for the most part, these super-intense puzzles stay that way. Fortunately, observatories have been set up to collect more direct data. Mergers (that is, violent collisions) between neutron stars and black holes can reveal The mass of the objects involved, as well as the nature of the neutron star’s matter.

projects Like NICER, NANOGrav, CHIME radio telescope, LIGO, Virgo, they all teach About physicists Neutron star size and structure.

More observational data can be fed into the models to get better estimates of the stars’ aspects. Ecker added that neutron stars that are very massive (in a football field of two solar masses) would be particularly useful in better constraining predictions of the physical properties of these extreme objects.

With any luck, we can soon Get more details on the exact ingredients of these giant cosmic candies – and how their recipes may vary depending on their size.

More: An extremely massive neutron star may be the largest ever observed

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