Strange, how to form a binary? Einstein's theory of relativity reveals for you.

There is a very unique binary star system in Musca constellation in the south. One of them is a pulsar, a pulsed neutron star, and another giant white dwarf star orbits each other once every five hours. Different from other binary systems composed of pulsars and white dwarfs, all models show that in this case, white dwarfs will form first, and then continue to absorb substances from stars until they explode, leaving only pulsars. The problem is that this is the case.

Concept drawing of MWC656 system. The star rotates very fast, releasing an equatorial disk, which is transmitted to the black hole through the accretion disk.

White dwarfs absorb matter, which will speed up their rotation. Stars are so weak that they are difficult to observe with the naked eye. Now astronomers have solved this problem by using a conjecture in general relativity-coordinate system drag effect. According to this theory, any celestial body will drag time and space when it rotates, which is also the Lunxi-Xiling effect. The surrounding environment of the earth has proved this, because the rotation of our planet will have a slight impact on the orbits of surrounding satellites.

Humans can't launch satellites around white dwarfs, but as Science magazine said, there is no need to do so. Pulsars are as accurate as clocks, and the intervals of radio waves emitted by magnetic poles are very accurate. The astronomical team spent 20 years collecting radio data and measuring the subtle changes of pulsar orbit, named pulsar J1141-6545.

Parks radio telescope. Image source free image.

White dwarfs and pulsars orbit each other once every five hours, and the drag effect is very weak. However, in 20 years, this star has been huge enough, and the research team predicted that the orbit of this pulsar would drift by about 150 km (93 miles), which is exactly what they observed.

Dr. William Van Straten, a scientist and co-author of the paper at Auckland University of Technology in New Zealand, explained: "After a series of potential experimental errors have been calculated in detail, there are indeed some deviations in the observation of pulsar J1141-6545, which are caused by the change of its orbital direction."

With reference to the theory of relativity and combined with the model, astronomers can determine the orbital parameters of two degenerate stars with similar mass and inclination. They also proposed that white dwarfs rotate around the axis every 100 second, thus confirming the hypothesis of the formation time of white dwarfs.

Double star:

A binary star is a star system in which two stars orbit the same center of mass. The brighter one is called the main star, and the other is the companion star or the second star. Studies from the beginning of19th century to the present show that many stars are actually part of galaxies, including binary systems or multi-star systems with more than two stars. The word "binary star" can be used as a synonym with another word "binary star", but generally speaking, the former can include the latter and can also refer to optical binary stars. An optical binary star consists of two stars, which are not physically related, but they are very close in the sky from the earth. If two stars in a binary star have obviously different self-advancing or radial velocities, or the distances between the two stars and the earth are different through parallax measurement, it can be determined that it belongs to an optical binary star. Most known binary systems are still uncertain whether they are binary systems or optical binary systems.

Binary star system is very important in astrophysics. Measuring their orbits can directly determine the mass of their constituent stars and indirectly estimate other star parameters, such as radius and density. At the same time, the empirical mass-luminosity relationship (MLR) can be determined, so as to estimate the mass of a single satellite.

Binary stars can usually be observed directly, and then they are generally called visual binary stars. Many visual binary stars have orbital periods of centuries or thousands of years, so astronomers are uncertain or know little about their orbits. Scientists can also use indirect techniques for detection and naming, such as spectroscopy (spectroscopic binary star) or astrometry (astrometric binary star). If the orbital planes of two stars lie almost flat in the observer's line of sight, the celestial bodies will devour each other, which is called eclipsing binary stars. In addition, during the eclipse and transition period, the binary stars judged by photometric changes are photometric binary stars.

Eat a double star. Source: 360 Encyclopedia.

If the stars in a binary system are very close, gravity will deform the atmosphere of the stars outside them. In some cases, these close binary systems will transfer matter to each other, which may lead to the future evolution to the point where a single star cannot be formed, such as the Great Ling Xing (eclipsing binary star), Sirius and Cygnus X- 1 (one of which may be a black hole). Binary star is the core of many planetary nebulae, and it is also the precursor of nova and type Ia supernova.

Author: Alfredo Ka Pignetti

FY: Ji Jun.

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