Because of the mutual movement between the three stars, they are not always in such a relative position. At present, proxima centauri is 4.25 light years away, and it is the closest star in the universe to the solar system. As they rotate, Alpha Centauri star C will one day move farther than the other two stars. So judging from the meaning of the name, the three stars should be called proxima centauri in turn.
Although Liu drew the planets in the neighboring galaxy by his own imagination when he wrote Three-body, in 20 16, astronomers discovered the exoplanet in the neighboring galaxy, namely the neighboring star B. Surprisingly, it is a terrestrial planet with a radius of about 1.07 times that of the earth and a mass of1of the earth.
Proxima b was discovered by the European Southern Observatory, and its official name is Alpha Centauri Cb (abbreviated as α Cen C b). It orbits proxima centauri at a distance of 0.0485 astronomical units, which is less than 1/20 of the distance between the sun and the earth, but the surface temperature of proxima centauri is only about half that of the sun (3,042 K), so the average surface temperature of the planet is lower than that of the earth, only about -39 degrees Celsius, and it is still in a livable zone.
However, this does not mean that neighboring star B is a livable planet. Scientists believe that red dwarfs like proxima centauri have strong far ultraviolet radiation, and it is easy to peel off the planet's atmosphere. So, even if the legendary three people really exist, I'm afraid the environment here is not friendly to them.
In 20 17, astronomers have suspected that there may be more than one planet in proxima centauri.
On June 5438+1October 65438+May this year, Fabio Del Sordo, an astronomer at the University of Crete, and Mario Damasso, a colleague of the Astrophysics Observatory in Turin, Italy, published the latest observation results in the journal Science Progress, pointing out that proxima centauri C does exist. They used the high-precision Radial Velocity Planet Searcher (HARPS) of the European Southern Observatory and the stepped spectra in ultraviolet and visible light (abbreviated as UVES) to find that there was an abnormal swing in proxima centauri in 17, and the swing led to the shift of the spectrum, which was probably caused by another planet. On April 20 19, they announced the news with a grain of salt, but this time they were obviously more confident.
In fact, the neighboring star B was discovered by astronomers in this way, which is the radial velocity method and the most effective means to find exoplanets at present. However, due to the factors of mass and distance, proxima centauri C has little influence on proxima centauri, and the deviation is only a few meters per second, which brings great difficulty to observation. It will take nearly 20 years and the joint efforts of the above two advanced equipment to find it.
Then, in April of 20 19, Damaso and Del soldo announced the possibility of discovering proxima centauri C, and it took nine months to finally publish their papers. The reason is that in 20 17, when researchers observed proxima centauri C with the Atacama MMW/MMW array (ALMA) located in Chile, they just found a strange signal, which may be another evidence of the existence of proxima centauri C. Unfortunately, despite repeated requests, they did not have the opportunity to use the telescope to find evidence again. Later, the observation results of Gaia satellite of the European Space Agency on the stars with a coefficient of one billion in the Milky Way also provided a little circumstantial evidence for the existence of proxima centauri C, so they finally published their paper. However, until now, the true identity of proxima centauri C has yet to be confirmed.
The reason that Gaia only provided a little evidence is that although the data tend to exist in proxima centauri Centauri C, its brightness is 10- 100 times higher than that of planets with the same mass. To explain this phenomenon, they speculated that there might be a lot of dust around proxima centauri C, or planetary rings, which led to brightness deviation. If the ring is right, the shape of proxima centauri C looks similar to Saturn's, which is 3-4 times the size of Saturn's ring.
Through proxima centauri's swing, they speculated that the mass of proxima centauri C was 6-8 times that of the Earth, which indicated that it was probably a gas planet and belonged to a mini Neptune. Observations show that the orbital period of proxima centauri C is about 1900 days, which is about 5.2 Earth years-this distance is enough to make it far beyond the snow line of proxima centauri and become a very cold world, and the temperature may be similar to the Kuiper Belt of the solar system, less than -200 degrees Celsius.
Although proxima centauri C is farther away from the host star than the first "three-body planet", the strong radiation from proxima centauri is likely to be very strong. However, astronomers believe that the magnetic field in proxima centauri C is relatively strong, so the magnetic field and the stellar wind in proxima centauri C are always "white-hot" above it, that is, the continuous aurora.
According to some solar system simulation data, the outer planets will throw comets farther inside to bomb the planets there in the early stage of formation. Moreover, proxima centauri C is much larger than its inner neighbor B, which is the same as the layout of the solar system. So it may not be too friendly to neighboring star B.
With the revolution of the earth, in July, the neighboring galaxies will be blocked by the sun's rays, which makes it impossible for us to observe, and it will not be observed again until February 20021year. Therefore, 2020 will leave us only about two months. However, with the development of the epidemic in COVID-19, it seems difficult for us to make a new breakthrough recently.
However, besides bad news, there is more good news.
Because proxima centauri C is far away from proxima centauri, we can look at the two celestial bodies from the earth from a larger angle, so we can use a relatively rare but effective method to find exoplanets-direct imaging method, and SPHERE is very good at this.
Not only that, Hawking's breakthrough shooting star project may also be added to the observation of proxima centauri C. Moreover, their goal is not only to observe neighboring galaxies, but also to launch thousands of nano-scale micro-spaceships and go to proxima centauri for field observation at a speed of 20% of the theoretical speed to tell people everything there.
As the closest star system to the solar system, neighboring galaxies have been widely concerned. The reason is not only that sci-fi works such as wandering earth describe the next stop of mankind, but also that such a close distance provides us with excellent observation opportunities. To be sure, astronomers will continue to observe all the troubles of neighboring galaxies. Even if there is no legendary threesome, there must be some cosmic secrets we want to know.