In summer, the sky on cloudless nights is especially beautiful. It seems that the number of flickering dots above the head has multiplied after the winter. In the northern hemisphere, almost in the middle of the celestial dome, right above the top of the observer you can see a rather bright star. This is Vega, the alpha of the constellation Lyra, a small celestial pattern located in such an advantageous place from the last days of spring to mid-autumn. The image of an antique musical instrument, despite its modest size compared to its neighbors, has long attracted the eyes of astronomers.
Environment and shape
The constellation Lyra contains 54 luminaries visible from the Earth to the naked eye. Its closest neighbors in the sky are Swan, Hercules, Dragon and Chanterelle. To find the brightest point of the picture, Vega, is quite simple not only due to its position. Alpha Lyra is one of the pinnacles of the Summer Triangle asterism, which consists entirely of very bright and well-marked stars. Two other corners of it are indicated by Deneb from the constellation Cygnus and Altair, relating to the celestial image of the Eagle.
The shape of the constellation Lyra resembles a quadrangle, all the peaks of which are clearly visible on a clear night. At a small distance from one of them is Vega.
Lyra constellation: legend
As you know, this heavenly figure bears the name of an ancient musical instrument. In ancient Greece, lyres were made from shells of turtles. The instrument was named after animals: the word "lyre" in translation means "turtle." According to legend, the first such object, capable of making melodic sounds, gave Hermes to people. 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 after her to the kingdom of the dead, tried to return, but at the last moment violated one of the main conditions of Hades. Having lost his beloved, Orpheus threw out his lyre and left in silence and sorrow to live out his life. The gods, awed by the sounds of the instrument, lifted it to heaven and made it a constellation.
Lovers
The Vega star is associated with a separate legend of eastern origin. Japanese and Chinese mythology correlates it with a beautiful goddess who fell in love with a mortal. The young man is also placed in heaven: this is Altair from the constellation Eagle. The goddess’s father, who learned of secret love, was 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 only allowed to meet once a year, on the seventh of July, when thousands of forty build a bridge between them. After the night, the goddess returns and with bitter tears mourns separation. Salt drops are seen from the Earth as falling meteors, Perseids.
Alpha
The brightest star in the constellation Lyra from ancient times attracted not only the eyes of storytellers. She was always interested in scientists. 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 takes fifth place in the whole 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 mass by 2.1 times, and its diameter by 2.3 times.
The future of the sun
Vega is a 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 portion of the Galaxy for 4.5 billion years. The radiation intensity and other characteristics will not allow the main star of Lyra to exist also for a long time. Astronomers predict Vega's extinction and destruction after about another 450 thousand years.
Standard
Thanks to its position, Vega has been well studied, which, in turn, served as its confirmation in the role of a certain standard in astronomy. Since the mid-19th century, the magnitude of several hundred luminaries has been determined by its brilliance. Vega became one of seven stars located at such a distance from the Sun that cosmic dust does not distort the radiation coming from them, on the basis of which the UBV photometric system was perfected, which allows one to determine some of the physical parameters of the bodies.
Despite the seemingly comprehensive study of Vega, there are a number of questions related to it, which to date have not received comprehensive answers. One of them undermines the "reputation" of alpha Lyra as a standard in astronomy. In the last century, "problems" were discovered in the brilliance of a star. The data obtained indicated that he was hesitating. In this case, Vegu should be attributed to variable stars. There is no unequivocal opinion on this subject yet.
Rotation
In the 60s of the 20th century, the habitual definition of the Vega spectral class also came into doubt. It turned out that Lyra's alpha is too hot and bright for standard representatives of its type. The fact did not receive a worthy explanation until 2005, when a clue was found.
It turned out that Vega rotates around its axis with great speed (in the region of the equator, the indicator reaches 274 km / s). Under such conditions, the shape of the space object changes. Vega is no more or less regular ball, but an ellipse elongated along the equator and flattened at the poles. As a result, contrary to custom, the northern and southern margins of the star are closer to the red-hot core than the equatorial zone. The poles are warmer stronger, glow brighter.
This hypothesis arose in the 80s of the last century and was confirmed by observations in 2005. It explains both the abnormal luminosity of the star and its brightness.
Disk
Vega is characterized by another feature: it has a circumstellar dust disk. She became the first luminary in which a similar formation was discovered. The disk consists of the remnants of space objects that collided with each other near the star.
The discovery of the disc was preceded by the detection of excess Vega infrared radiation. Today, all luminaries with a similar characteristic are designated as "veg-like."
Some features in the structure of the dust disk suggest that a huge planet, similar to Jupiter, revolves around alpha Lyra. Until these data are confirmed, however, if this happens, Vega will become the first brightest star to own a planet.
Sheliak
Among the interesting objects of a heavenly musical instrument is not only Vega. The constellation Lyra has several multiple star systems. The attention of scientists is primarily attracted by Sheliak, beta Lyra. It refers to the eclipsing variable luminaries. The system consists of a bright blue-white dwarf and a large, but dimmer white star, belonging to the main sequence. They are separated by 40 million kilometers, which by space standards is very small. As a result, the substance from one of the partners continuously flows onto the other.
Gas moving from the "donor" forms an accretion disk around the "recipient". In this case, both stars are surrounded by a common gas shell, which constantly gives away part of its substance to the surrounding space.
Initially, the 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, while this parameter of the companion is equal to 13 masses of our luminary.
At a certain distance from the main pair, there is a third star, beta Lyra B. In brightness, it is 80 times greater than the Sun. Beta Lyra B refers to spectroscopic doubles (period is 4.34 days).
Epsilon
The constellation Lyra also has a stellar system consisting of four components. This is Epsilon Lyra, divided into two components Epsilon 1 and Epsilon 2 even when observed with binoculars. Each of them is a pair of luminaries. All four components are white stars belonging to the same spectral class as Sirius. Epsilon 1 and 2 rotate with a period of 244 thousand years.
Ring and ball
Virtually any celestial figure boasts beautiful nebulae in its "territory". Not an exception and the constellation Lyra. A photo of a space object located between the gamut and beta of Lyra gives a clear idea of the origin of its name.
The Nebula Ring, in its form, 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 at 5.5 thousand years. You can see it with binoculars. The beautiful glow of the nebula is due to the ultraviolet radiation emitted by the white dwarf. Once it was the core of a massive star.
Not far from the nebula is the globular star cluster M56.
Their neighborhood, however, is imaginary: M56 is 32.9 thousand light-years distant from Earth. In the pictures it resembles a ball condensed to the middle, where the number of stars per unit of space is quite high. Here are located about 12 variable stars. The globular cluster is difficult to observe with the help of amateur equipment, since it is lost against the background of the Milky Way.
Lyra is a small constellation, but nevertheless interesting. Representatives of very many objects from those studied by astronomy are located on its “territory”. The stars and constellations surrounding Lira may seem more impressive and worthy of attention. On the other hand, Vega alone is enough to “overshadow” them all. Especially if you recall that the stellar magnitudes of these luminaries, quite possibly, were determined on the basis of data on alpha Lyra. This heavenly drawing, therefore, is a graphic illustration of the proverb “small yes daring”. However, the same can be said about his legendary prototype, the lyre of Orpheus.