What star systems exist?

Stars are needed, the stars are all important ... But are not all stars in the sky the same? Strangely enough, no. Star systems have different structures and different classifications of their components. And even the luminary in another system may not be one. It is on this basis that the scientists of the star system of the galaxy are distinguished first and foremost.

Before proceeding directly to the classification, it is worthwhile to clarify what will be discussed at all. So, star systems are galactic units, consisting of stars rotating along a fixed path and interconnected gravitationally. In addition, there are planetary systems, which, in turn, consist of asteroids and planets. So, for example, the obvious example of a star system is Solar, familiar to us.

However, not the whole galaxy is filled with such systems. Star systems are primarily different in multiplicity. It is clear that this value is very limited, since for a long time a system with three or more equivalent stars can not exist. Sustainability can only guarantee a hierarchy. For example, that the third stellar component does not appear "outside the gate", it should not approach a stable binary system closer than 8-10 radii. In this case, it is not necessary that he was single - it could well be a double star. In general, for 100 stars about thirty - single, forty-seven - double, twenty-three - multiple.

Multiple stars

Unlike constellations, multiple stars are interconnected by mutual gravitation, being located, at the same time, a short distance from each other. They move together, revolving around the center of mass of their system - the so-called barycenter.

A striking example is Mizar, known to us by the constellation Ursa Major. It is worth paying attention to her "pen" - her middle star. Here you can see the dimmer glow of her couple. Mizar Alcor - a double star, you can see it without special tools. If you use a telescope, it becomes clear that Mizar-double itself, consisting of components A and B.

Double stars

Star systems, in which two luminaries are discovered, are called double stars. Such a system will be completely stable if there are no tidal effects, mass transfer of stars and disturbances of other forces. In this case, the luminaries move in an elliptical orbit almost infinitely, rotating around the center of mass of their system.

Visually-binary stars

Those pair stars, which can be seen in a telescope or even without devices, are usually called visually-double. Alpha Centauri, for example, is such a system. The starry sky is rich in similar examples. The third luminary of this system is the closest of all to our own - Proxima Centauri. Most often, these halves of the pair differ in color. So, Antares has a red and green star, Albireo - blue and orange, Beta Swan - yellow and green. All these objects can be easily observed in a lens telescope, which enables specialists to confidently calculate the coordinates of the luminaries, their speed and direction of motion.

Spectral binary stars

It often turns out that one star of a star system is too close to the other. So much so that even the most powerful telescope can not grasp their duality. In this case, the spectrometer comes to the rescue. When passing through the instrument, the light decomposes into a spectrum delineated by black lines. These bands are shifted as the light is approached or removed from the observer. When the spectrum of a binary star is decomposed, two types of lines are obtained that shift when the two components move around each other. So, Mizar A and B, Alcor - spectral-double. At the same time, they are also united in a large system of six stars. Also, the visual-double components Castor - a star in the constellation Gemini - are spectrally-double.

Visible-binary stars

There are other star systems in the galaxy. For example, those whose components are moved in such a way that the plane of their orbits is close to the line of sight of the observer from the Earth. This means that they obscure each other, creating mutual eclipses. During each of them we can observe only one of the luminaries, while their total luster decreases. In the case when one of the stars is much larger, this decrease is noticeable.

One of the most well-known noticeable-double stars is Algol from the Perseus constellation. With a clear periodicity of 69 hours, its brightness falls to the third value, but after 7 hours it again increases to the second. This star is often called the "Winking Devil". It was discovered in 1782 by an Englishman, John Goudrayke.

From our planet, the noticeable-double star looks like a variable that changes brightness after a certain time interval, which coincides with the period of revolution of the stars around each other. Such stars are still called markedly variable. In addition to them, there are physically variable luminaries - the cipheids, whose brightness is regulated by internal processes.

Evolution of binary stars

More often than not, one of the stars in a binary system is a larger, rapidly passing cycle of life. While the second star remains normal, its "half" turns into a red giant, then into a white dwarf. The most interesting thing in such a system begins when the second star turns into a red dwarf. White in this situation attracts the accumulated gases of the expanding "fellow". About 100 thousand years is enough for the temperature and pressure to reach the level necessary for nuclear fusion. The gas shell of the star explodes with incredible force, resulting in the luminosity of the dwarf increases almost a million times. Observers from Earth call this the birth of a new star.

Astronomers happen to discover and such situations, when one of the components is an ordinary star, and the second - a very massive, but invisible, with an acceptable source of powerful X-ray radiation. This makes it possible to assume that the second component is a black hole - the remains of a once massive star. Here, according to experts, the following occurs: using powerful gravity, a black hole attracts star gases. Drawing in a spiral at a tremendous speed, they heat up, releasing energy before the disappearance in the hole in the form of X-rays.

Scientists have concluded that a powerful source of X-ray radiation proves the existence of black holes.

Triple Star Systems

The solar stellar system, as can be seen, is by no means the only version of the structure. In addition to a single and a double star, more of them can be observed in the system. The dynamics of such systems is much more complicated than even the double one. However, sometimes there are stellar systems with a small number of luminaries (exceeding, however, two units), which have rather simple dynamics. Such systems are called multiple. If the stars entering the system are three, it is called triple.

The most common is this kind of multiple systems - triple. So, back in 1999 in the catalog of multiple stars from 728 multiple systems more than 550 are triple. In accordance with the principle of hierarchy, the composition of these systems is as follows: two stars are closely located, one is strongly removed.

In theory, the model of a multiple star system is much more complex than double, since such a system can show chaotic behavior. Many such clusters are, in fact, very unstable, which leads to the ejection of one of the stars. Avoid this scenario can only those systems, the stars in which are located on a hierarchical basis. In such cases, the components are divided into two groups, rotating around the center of mass in a large orbit. Within groups, there must also be a clear hierarchy.

Higher multiplicities

Scientists know of stellar systems and with a large number of components. So, Scorpio has more than seven luminaries in its composition.

So, it turned out that not only the planets of the star system, but also the systems in the galaxy are not the same. Each of them is unique, different and extremely interesting. Scientists are discovering an increasing number of stars, and perhaps soon we will learn about the existence of an intelligent life not only on our own planet.