Proxima Centauri is a star that is closest to Earth. She received the name from the Latin word proxima, which means "closest." 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 pioneer of the star was Robert Innes, an astronomer from Scotland.
Alpha Centauri Star System
Proxima is part of the
Alpha Centauri system. In addition to her, she 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 "The Centaur's Foot." 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 noticeable in the night sky.
Alpha Centauri B is also not inferior to the "sister" in brightness. Together they are a close binary system. Proxima Centauri is quite far from them. Between the stars is a distance of thirteen thousand astronomical units (this is farther than from the Sun to the planet Neptune four hundred times!).
All the stars of the Centauri system rotate in orbit around their common center of mass. Only Proxima moves very slowly: the period of her circulation takes millions of years. Therefore, this star will remain very close to the Earth for a very long time.
Quite small
The star of Proxima Centauri is not only the closest of the constellations to us, but is also the smallest. Its mass is so scanty that it is barely enough to support the processes of helium formation from hydrogen necessary for existence. The star glows dimly. Proxima is much lighter than the Sun, about seven times. And the temperature on its surface is much lower: “only” three thousand degrees. By brightness, Proxima is inferior to the Sun one hundred and fifty times.
Red dwarfs
The small asterisk Proxima belongs to the spectral class M with very low luminosity. The other name for the celestial bodies of this class is widely known - red dwarfs. Stars with such a small mass are interesting objects. Their internal structure is somewhat similar to the structure of giant planets such as Jupiter. The substance of red dwarfs is in an exotic state. In addition, there are suggestions that the planets that are located near such stars may be suitable for life.
Red dwarfs live a very long time, much longer than any other stars. They evolve very slowly. Any nuclear reactions within them begin to occur only a few billion years after their inception. The life time of the red dwarf is longer than the lifetime of the whole Universe! So, in the distant, distant future, when more than one star like the Sun goes out, the red dwarf of Proxima Centauri will also still dimly shine in the darkness of space.
In general, red dwarfs are the most frequent stars in our galaxy. More than 80% of all the stellar bodies of the Milky Way are they. And here is the paradox: they are completely invisible! With the naked eye you will not notice any of them.
Measurement
Until now, the ability to accurately measure the size of such small stars as red dwarfs, because of their weak luminosity, has simply not been possible. But today this problem has been solved with the help of a special VLT-interferometer (VLT - short for 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 distant from each other, make it possible to measure celestial bodies with such accuracy that other devices simply cannot afford. So astronomers of the Geneva Observatory for the first time received the exact dimensions of such a small star.
Changeable Centauri
By its size, Proxima Centauri borders on a real star, planet and
brown dwarf. And yet it is a star. Its mass and diameter are one seventh of the mass, as well as the
diameter of the Sun, respectively. The star is more massive than the planet Jupiter, a hundred and fifty times, but it weighs one and a half times less. If Proxima Centauri weighed even less, then she simply could not become a star: there would not be enough hydrogen in her bowels to radiate 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 will look bright only on pictures taken by huge telescopes, such as, for example, Hubble. However, sometimes the brilliance of a star increases sharply and significantly. Scientists explain this fact by the fact that Proxima Centauri belongs to the class of so-called changeable, or flashing, 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 quite a child
These turbulent processes and outbreaks suggest that the nuclear reactions taking place in the bowels of Proxima Centauri have not yet stabilized. Conclusions of scientists: this is still a very young star by the standards of space. Although her age is quite comparable with the age of our sun. But Proxima is a red dwarf, so they can not even be compared. Indeed, like other "red brothers", it will very slowly and economically burn its nuclear fuel, and therefore will shine for a very, very long time - 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 planets are hidden in her universe where other civilizations can be found. Maybe it is, but the distance from Earth to Proxima Centauri is only four light years. So, although it is the closest, it is still far away.