Proxima Centauri is the closest star to Earth. It got its name from the Latin word proxima, which means "nearest". The distance from it to the Sun is 4.22 light years. However, despite the fact that the star is closer to us than the Sun, it can only be seen through a telescope. It is so small that nothing was known of its existence until 1915. The star was discovered by Robert Innes, an astronomer from Scotland.
Star system Alpha Centauri
Proxima is part of the Alpha Centauri system. In addition to it, it also includes two more stars: Alpha Centauri A and Alpha Centauri B. They are much brighter and more noticeable than Proxima. So, star A, the brightest in this constellation, is located at a distance of 4.33 light years from the Sun. It is called the Rigel Centauri, which translates as "Centaur Leg". This star is somewhat reminiscent of our Sun. Probably because of its brightness. Unlike Proxima Centauri, it has been known since ancient times, as it is very visible in the night sky.
Alpha Centauri B is also not inferior to its "sister" in brightness. Together they form a close binary system. Proxima Centauriis far enough away from them. Between the stars - a distance of thirteen thousand astronomical units (that's four hundred times further from the Sun to the planet Neptune!).
All stars in the Centauri system orbit around their common center of mass. Only Proxima moves very slowly: the period of its revolution takes millions of years. Therefore, this star will remain the closest to Earth for a very long time.
Very small
The star Proxima Centauri is not only the closest of the constellation to us, but is also the smallest. Its mass is so tiny that it is barely enough to support the processes of formation of helium from hydrogen, which are necessary for existence. The star is very dim. Proxima is much lighter than the Sun, about seven times. And the temperature on its surface is much lower: "only" three thousand degrees. In terms of brightness, Proxima is one hundred and fifty times inferior to the Sun.
Red dwarfs
The small star Proxima belongs to the spectral type M with a very low luminosity. Another name for celestial bodies of this class is widely known - red dwarfs. Stars with such a small mass are the most interesting objects. Their internal structure is somewhat similar to the structure of giant planets such as Jupiter. The matter of red dwarfs is in an exotic state. In addition, there are suggestions that planets that are located near such stars may be habitable.
Red dwarfs live a very long time, muchlonger than any other stars. They evolve very slowly. Any nuclear reactions inside them begin to occur only a few billion years after their birth. The lifetime of a red dwarf is longer than the lifetime of the entire universe! So, in the far, far future, when more than one star like the Sun goes out, the red dwarf Proxima Centauri will still shine dimly in the darkness of space.
In general, red dwarfs are the most frequent stars in our galaxy. More than 80% of all stellar bodies in the Milky Way are they. And here is the paradox: they are completely invisible! None of them can be seen with the naked eye.
Measurement
Until now, the ability to accurately measure the size of such small stars as red dwarfs, due to their weak luminosity, was simply not possible. But today this problem has been solved with the help of a special VLT interferometer (VLT is an abbreviation for the English Very Large Telescope). This is an apparatus based on two large 8.2-meter VLT telescopes located at the Paranal Astronomical Observatory (ESO). These two huge telescopes, 102.4 meters apart, make it possible to measure celestial bodies with such accuracy that other devices simply cannot. This is how astronomers at the Geneva Observatory obtained the exact dimensions of such a small star for the first time.
Changeable Centauri
In size, Proxima Centauri borders between a real star, a planet and a brown dwarf. And yet it is a star. Its mass and diameter are oneseventh of the mass, and also the diameter of the Sun, respectively. The star is one hundred and fifty times more massive than the planet Jupiter, but weighs one and a half times less. If Proxima Centauri weighed even less, then it simply could not become a star: there would not be enough hydrogen in its depths to emit light. In this case, it would be an ordinary brown dwarf (i.e. dead), and not a real star.
Proxima itself is a very dim celestial body. In the normal state, its luminosity reaches no more than 11m. It looks bright only in pictures taken by huge telescopes, such as, for example, Hubble. However, sometimes the brightness of a star is sharply and significantly enhanced. Scientists explain this fact by the fact that Proxima Centauri belongs to the class of so-called changeable, or flaring, stars. This is caused by strong flashes on its surface, which are the results of violent convection processes. They are somewhat similar to those that occur on the surface of the Sun, only much stronger, which even leads to a change in the brightness of the star.
Still a baby
These violent processes and outbreaks indicate that the nuclear reactions occurring in the bowels of Proxima Centauri have not yet stabilized. The conclusions of scientists: this is still a very young star by the standards of space. Although its age is quite comparable with the age of our Sun. But Proxima is a red dwarf, so they can't even be compared. After all, like other "red brothers", it will burn its nuclear fuel very slowly and economically, and therefore shine very, verylong - about three hundred times longer than our entire universe! What can I say about the Sun…
Many science fiction writers believe that Proxima Centauri is the most suitable star for space exploration and adventure. Some believe that her universe hides planets where other civilizations can be found. Maybe it is, but that's just the distance from the Earth to Proxima Centauri - more than four light years. So, even though it is the closest, it is still far away.
