The life cycle of a star is a description, diagram and interesting facts

Stars, like people, can be newborn, young, old. Every moment some stars die and others are formed. Usually the youngest of them are like the Sun. They are at the stage of formation and in fact represent protostars. Astronomers call them T-Tauri stars, named after their prototype. By their properties - for example, luminosity - protostars are variable, because their existence has not yet entered a stable phase. A lot of them are around a lot of matter. From the T-type stars, powerful wind currents emanate.

Protostars: the beginning of the life cycle

If a substance falls on the surface of a protostar, it quickly burns and turns into heat. As a result, the temperature of protostars is constantly increasing. When it rises so much that nuclear reactions start at the center of the star, the protostar takes on the status of an ordinary one. With the onset of the course of nuclear reactions, a constant source of energy appears in the star, which maintains its vital activity for a long time. How long will the life cycle of a star in the universe depend on its original size. However, it is believed that the stars, the diameter of the Sun, the energy is enough to comfortably exist for about 10 billion years. Despite this, it also happens that even more massive stars live only a few million years. This is due to the fact that they burn their fuel much faster.

Stars of normal size

Each of the stars is a bunch of hot gas. In their depths, the process of developing nuclear energy is constantly taking place. However, not all stars are like the Sun. One of the main differences is the color. The stars are not only yellow, but also bluish, reddish.

Brightness and luminosity

They differ and by such signs, as shine, brightness. How bright the observed star from the surface of the Earth will be depends not only on its luminosity, but also on the remoteness from our planet. Considering the distance to the Earth, the stars can have completely different brightness. This figure ranges from one ten thousandth of the brightness of the Sun to a brightness comparable to more than a million Suns.

Most of the stars are on the lower part of this spectrum, being dim. In many respects, the Sun is an average, typical star. However, compared to others, it has much greater brightness. A large number of dim stars can be observed even with the naked eye. The reason why stars differ in brightness is their mass. Color, gloss and brightness change over time are determined by the amount of matter.

Attempts to explain the life cycle of stars

People have long tried to follow the life of stars, but the first attempts of scientists were rather timid. The first achievement was the application of Lane's law to the Helmholtz-Kelvin hypothesis on gravitational compression. This brought to astronomy a new understanding: theoretically, the temperature of the star should increase (its index is inversely proportional to the radius of the star) until the increase in density slows down the compression processes. Then the energy consumption will be higher than its arrival. At this point the star will begin to cool down rapidly.

Hypotheses about the life of stars

One of the original hypotheses about the life cycle of a star was proposed by astronomer Norman Lokier. He believed that stars arise from meteoric matter. In this case, the provisions of his hypothesis relied not only on the theoretical conclusions available in astronomy, but also on the data of the spectral analysis of stars. Lockier was convinced that the chemical elements that participate in the evolution of celestial bodies consist of elementary particles - "proto-elements." Unlike modern neutrons, protons and electrons, they have not a common but an individual character. For example, according to Lokier, hydrogen decomposes into a so-called "proto-hydrogen"; Iron becomes a "proto-iron". Other astronomers, such as James Hopwood, Jacob Zeldovich, Fred Hoyle, tried to describe the life cycle of a star.

Stars are giants and star-dwarfs

Stars of large sizes are the hottest and brightest. They are usually white or bluish in appearance. Despite the fact that they have huge dimensions, the fuel inside them burns so quickly that they lose it for some several million years.

Stars of small sizes, as opposed to gigantic ones, are usually not so bright. They have a red color, live long enough - for billions of years. But among the bright stars in the sky there are also red and orange. An example is the star Aldebaran - the so-called "eye of a bull", located in the constellation of Taurus; As well as Antares star in the constellation Scorpio. Why are these cold stars capable of competing in brightness with red-hot stars, like Sirius?

This is due to the fact that once they greatly expanded, and by their diameter, they began to outperform huge red stars (supergiants). The huge area allows these stars to radiate an order of magnitude more energy than the Sun. And this despite the fact that their temperature is much lower. For example, the diameter of Betelgeuse, located in the constellation of Orion, is several hundred times larger than the diameter of the Sun. And the diameter of ordinary red stars usually does not amount to a tenth of the size of the Sun. Such stars are called dwarfs. These kinds of life cycle of stars can pass through each celestial star - the same star in different parts of its life can be both a red giant and a dwarf.

As a rule, luminaries like the Sun maintain their existence due to hydrogen inside. It turns into helium inside the nuclear core of the star. The sun has a huge amount of fuel, but even it is not infinite - over the past five billion years, half of the stock has been spent.

The lifetime of the stars. Life cycle of stars

After the hydrogen is exhausted inside the star, serious changes come. The remains of hydrogen begin to burn not inside its core, but on the surface. At the same time, the star's lifetime decreases more and more. The cycle of stars, at least, most of them, on this segment passes into the stage of the red giant. The size of the star becomes larger, and its temperature, on the contrary, is smaller. This is how most red giants appear, as well as supergiants. This process is part of the overall sequence of changes occurring with the stars, which scientists called the evolution of stars. The cycle of life of a star includes all its stages: eventually all stars grow old and die, and the duration of their existence is directly determined by the amount of fuel. Big stars end their lives with a huge, spectacular explosion. More modest, on the contrary, perish, gradually shrinking to the size of white dwarfs. Then they just fade away.

How long does the average star live? The life cycle of a star can last from less than 1.5 million years and up to 1 billion years or more. All this, as has been said, depends on its composition and size. Stars like the Sun live from 10 to 16 billion years. Very bright stars, like Sirius, live relatively briefly - only a few hundred million years. The scheme of the life cycle of a star includes the following stages. This molecular cloud - the gravitational collapse of the cloud - the birth of a supernova - the evolution of the protostar - the end of the protostellar phase. Then follows the stages: the beginning of the stage of the young star - the middle of life - the maturity - the stage of the red giant - the planetary nebula - the stage of the white dwarf. The last two phases are peculiar to stars of small size.

Nature of planetary nebulae

So, we have briefly reviewed the life cycle of a star. But what is the planetary nebula? Turning from a huge red giant into a white dwarf, sometimes stars throw off the outer layers, and then the core of the star becomes naked. The gas shell begins to glow under the action of the energy radiated by the star. The name of this stage was obtained due to the fact that the glowing gas bubbles in this shell often look like discs around the planets. But in reality they have nothing in common with planets. The life cycle of stars for children may not include all scientific details. One can only describe the main phases of the evolution of the heavenly bodies.

Star Clusters

Astronomers are very fond of exploring stars. There is a hypothesis that all the luminaries are born in groups, and not individually. Since stars belonging to the same cluster have similar properties, the differences between them are true, and not caused by the distance to the Earth. No matter what changes these stars make, these beginnings are taken at the same time and under equal conditions. Especially a lot of knowledge can be obtained by studying the dependence of their properties on mass. After all, the age of stars in clusters and their distance from the Earth are approximately equal, so they differ only in this indicator. Clusters will be interesting not only to professional astronomers - every amateur will be happy to make a beautiful photo, to admire their exceptionally beautiful view in the planetarium.