Summer sky on cloudless nights is especially beautiful. It seems that the number of flickering dots above the head after the winter has increased many times over. In the northern hemisphere, almost in the middle of the celestial dome, right above the crown of the observer, you can see a rather bright star. This is Vega, the alpha of the constellation Lyra, a small celestial figure located in such a favorable place from the last days of spring to the middle of autumn. The image of an ancient musical instrument, despite its modest size compared to its neighbors, has attracted the eyes of astronomers since ancient times.
Environment and shape
The constellation Lyra contains 54 luminaries visible from Earth with the naked eye. Her closest neighbors in the sky are Cygnus, Hercules, Dragon and Chanterelle. Finding the brightest point of the picture, Vega, is quite easy, not only because of its position. Alpha Lyrae is one of the peaks of the Summer Triangle asterism, which consists entirely of very bright and highly visible stars. Its other two corners are marked by Deneb from the constellation Cygnus and Altair, referring to the celestial image of the Eagle.
The shape of the constellation Lyra resembles a quadrangle, all the tops of which are clearly visible on a clear night. Vega is located a short distance from one of them.
Constellation Lyra: legend
As you know, this celestial drawing bears the name of an ancient musical instrument. In ancient Greece, lyres were made from tortoise shells. In honor of the animals, the instrument was named: the word "lyre" in translation means "tortoise". According to legend, the first such object capable of making melodic sounds was presented to people by Hermes. Lyra always accompanied the mythical singer Orpheus. According to legend, his music and voice captivated both gods and people. Where the sounds of the lyre were heard, flowers bloomed and birds sang. Orpheus had a difficult fate: he lost his wife, Eurydice, went down to the kingdom of the dead after her, tried to return her, but at the last moment violated one of the main conditions of Hades. Having lost his beloved, Orpheus threw away the lyre and left in silence and sorrow to live out his life. The gods, in awe of the sounds of the instrument, took it to heaven and made it a constellation.
Lovers
The star Vega is associated with a separate legend of Eastern origin. Japanese and Chinese mythology correlates her with a beautiful goddess who fell in love with a mortal. The young man is also placed in the sky: this is Altair from the constellation Eagle. The father of the goddess, who found out about secret love, became angry and forbade his daughter to meet with the chosen one. Since then, Vega and Altair have been separated by a celestial river, the Milky Way. Lovers are allowed to meet only once inyear, on the seventh of July, when forty thousand build a bridge between them. At the end of the night, the goddess comes back and mourns the separation with bitter tears. S alty drops are seen from Earth as falling meteors, the Perseids.
Alpha
The brightest star in the constellation Lyra has long attracted not only the eyes of storytellers. Scientists have always been interested in it. The unique position of the star and its visibility led to the fact that today Vega is one of the most studied stars in space.
In terms of brightness, it ranks fifth in the entire sky and second in the northern hemisphere after Arcturus. The apparent magnitude of Vega is 0.03. It belongs to the objects of the spectral class A0Va, its mass exceeds the solar one by 2.1 times, and its diameter is 2.3.
The future of the luminaries
Star Vega - blue and white giant. According to scientists, it has been shining for 455 thousand years. For a person, this is an amazing figure, but by the standards of the Universe, Vega does not live that long. For comparison, the Sun has been illuminating our section of the Galaxy for 4.5 billion years. The intensity of radiation and other characteristics will not allow the main star of Lyra to exist for such a long time. Astronomers predict Vega will fade and collapse after about another 450,000 years.
Standard
Due to its position, Vega has been well studied, which, in turn, served to establish it as a certain standard in astronomy. Since the middle of the 19th century, the stellar magnitudes of several hundred luminaries have been determined from its brilliance. Vega became one of the seven stars located on suchdistance from the Sun, that cosmic dust does not distort the radiation coming from them, on the basis of which the UBV photometric system was brought to perfection, which makes it possible to determine some physical parameters of the luminaries.
Despite the seemingly comprehensive study of Vega, there are a number of related questions that have not yet received exhaustive answers. One of them undermines the "reputation" of alpha Lyra as a standard in astronomy. In the last century, "malfunctions" in the brightness of the star were discovered. The data obtained indicated that it fluctuated. In this case, Vega should be attributed to variable stars. There is no unequivocal opinion on this yet.
Rotation
In the 60s of the 20th century, the usual definition of the spectral type of Vega was also questioned. It turned out that Lyra's alpha is too hot and bright for the standard representatives of her type. The fact did not receive a worthy explanation until 2005, when the solution was found.
It turned out that Vega rotates around its axis at high speed (near the equator, the figure reaches 274 km/s). Under such conditions, the shape of the space object changes. Vega is no more or less a regular sphere, but an ellipse, elongated along the equator and flattened at the poles. As a result, contrary to usual, the northern and southern outskirts of the star are located closer to the hot core than the equatorial zone. The poles heat up more, glow brighter.
This hypothesis arose in the 80s of the last century and was confirmed by observations in 2005. It also explains the anomalous luminositystars and their brightness.
Disc
Vega is characterized by another feature: it has a circumstellar dust disk. She became the first luminary in which such a formation was discovered. The disk consists of the remnants of space objects that collided with each other near the star.
The discovery of the disk was preceded by the discovery of an excess of infrared radiation from Vega. Today, all luminaries with a similar characteristic are referred to as "Vega-like".
Some features in the structure of the dust disk suggest that a huge Jupiter-like planet revolves around Alpha Lyra. While this data is not confirmed, but if it happens, Vega will become the first brightest star to possess a planet.
Sheliac
Vega is not the only interesting object of the celestial musical instrument. The constellation Lyra has several multiple star systems. The attention of scientists is primarily attracted by Sheliak, the beta of Lyra. It belongs to the eclipsing variable luminaries. The system consists of a bright blue-white dwarf and a large but dimmer main-sequence white star. They are separated by 40 million kilometers, which is very small by space standards. As a result, the substance from one of the companions continuously flows to the other.
The gas moving from the "donor" forms an accretion disk around the "recipient". At the same time, both stars are surrounded by a common gaseous shell, which constantly gives off part of its substance to the surrounding space.
Originallythe mass ratio of the companions looked different. Today's donor was more impressive. Over time, he turned into a giant and began to give his substance. Now its mass is estimated at 3 solar masses, while this parameter for the companion is 13 masses of our star.
At some distance from the main pair is the third star, Beta Lyra B. It is 80 times brighter than the Sun. Beta Lyrae B is a spectroscopic binary (the period is 4.34 days).
Epsilon
The constellation Lyra also has a star system consisting of four components. This is Lyrae's epsilon, splitting into two parts, Epsilon 1 and Epsilon 2, even when viewed with binoculars. Each of them is a pair of luminaries. All four components are white stars belonging to the same spectral type as Sirius. Epsilon 1 and 2 rotate with a period of 244 thousand years.
Ring and ball
Almost any celestial drawing boasts beautiful nebulae in its "territory". The constellation Lyra is no exception. A photo of a space object located between gamma and beta Lyra gives a clear idea of the origin of its name.
Nebula The shape of the ring really resembles the corresponding piece of jewelry. It adorns the constellation Lyra, located at a distance of 2 thousand light years from Earth. The age of the nebula is estimated to be 5.5 thousand years. You can see it with binoculars. The beautiful glow of the nebula is due to ultraviolet light.radiation emitted by the white dwarf. It was once the core of a massive star.
The globular star cluster M56 is located not far from the nebula.
Their neighborhood, however, is imaginary: M56 is 32.9 thousand light-years away from the Earth. In the pictures, it resembles a ball, compacted towards the middle, where the number of stars per unit of space is quite high. There are approximately 12 variable stars here. The globular cluster is difficult to observe with amateur equipment because it is lost against the background of the Milky Way.
Lyra is a small constellation, but nevertheless interesting. On its "territory" there are representatives of very many objects from among those that are studied by astronomy. The stars and constellations surrounding Lyra may seem more imposing and noteworthy. On the other hand, bright Vega alone is enough to “outshine” them all. Especially if we remember that the stellar magnitudes of these luminaries, quite possibly, were determined on the basis of data on Lyra's alpha. This heavenly drawing, therefore, is a clear illustration of the saying "small and bold." However, the same can be said about his legendary prototype, the lyre of Orpheus.
