Researchers of the Astronomical Museum found the clues of the mystery of extremely bright X -ray pulse stars

When normal stars have exhausted their core fuel, they will die, leaving a dense remains, including white dwarfs, neutron stars, and black holes. The quality of the Miying Star is similar to normal stars, but the size is much smaller. For example, the neutron star radius is about 10 kilometers, and only one in 100,000 in the radius of the sun.

Because the dense star is too small, it is difficult for us to see them. Even through telescopes, it is difficult to find them. However, because they are extremely dense, under the circumstances of the conditions, such as a normal star around them can provide substances, causing the Star to generate strong radiation by sucking substances. This is because their density can provide a strong gravity attraction. Near the dense star, the extremely fast speed thermal heating of the substance can produce a strong high -energy X -ray radiation (such as the black and white map). This method of suction capacity is dozens of times higher than the nuclear fusion of normal stars!

X -ray pulse star's accumulation process schematic diagram

Therefore, we can observe the neutron stars in accumulation through the X -ray telescope. The energy (optical) of the light emitted per second is about 4X1026 watts, and the light of the medium star can generally be 100,000 times higher than that of the sun! However, the luminous power of the small star star is not unlimited. If its light is too high, the light will blow away the accumulated substances, causing the accumulation to be proceeded (Edinton limit). This is just like the wind will blow the sailing boat. People are already designing the detector to send the detector to the neighboring star through the light sail.

In the past, people thought that the upper limit of the neutron star was about 100,000 times the sunlight. In 2014, a X -ray pulse star was found in the shape of the Star Stranger M82 (the famous cigar galaxy, the shape of the X -ray band), which was completely different from the optical band), which reached one million times the light of the sun! The cause of this newly discovered extremely bright X -ray pulse star is an unsolved puzzle: Why can small neutron stars emit such a high degree of light? (The quality of the neutron stars is between 1-3 times the quality of the sun. If it is too high, it will collapse into a black hole. The black hole does not have a hard surface and does not produce a stable pulse signal.)

When studying the first extremely bright X -ray pulse star in the Milky Way (Swift J0243, outbreak in October 2017), using my country's wisdom -eye X -ray telescope (launched in June 2017), researchers and collaborators of Beijing Astronomical Museum discovered Swift When J0243 is high in light, its radiation mode changes, and from a low -light picker mode to a fan mode perpendicular to the magnetic line, it is consistent with the picture of the accumulated pillar when the theoretical expects highlight (such as the highlights of the theoretical expectations (such as Lottery)!

Pencil radiation mode at low light

Fan radiation mode during highlights

Swift J0243 forms a high -light pillar that requires a strong magnetic field. It is estimated that it is about 1.5x1013 Gauss, which is higher than the magnetic field of ordinary X -ray pulse stars (generally less than 1x1013 Gauss). This means that the extremely bright X -ray pulse star is likely to be a neutron star with a high magnetic field! (Another work of the Huidan Telescope team confirmed this extremely high magnetic field.)

They also found that the pulse contour of Swift J0243 changed at highlights. Among them, the self -transition speed of the sub -star became more inefficient than when the accumulation substances generally caused the neutron star to turn faster). These high -light strange phenomena are likely to be caused by the strong radiation of the accumulated pillar that change the geometry of the accumulation material flow. The results of these studies provided clues to the mystery of extremely bright X -ray pulse stars.

For details, reference link:

https://arxiv.org/abs/2203.12227

(Liu Jizi)

Public account name: Beijing Institute of Science and Technology, Beijing Science and Technology Research Institute

WeChat: BJAST-WX

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