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[Vega] Located in the east of the Milky Way, a star opposite Altair across the Milky Way belongs to Lyra, about 27 light years away from the Earth. It is bluish white, the brightest star in this constellation, with a surface temperature as high as 10000℃. Weaver Girl I is a bright star in Lyra, and its scientific name is Lyra-α. It is one of the most famous bright stars in the summer night sky. Usually, people call it Vega. In the west, it is called "Queen of Summer Night". In China, the fairy tale of Cowherd and Weaver Girl is widely circulated: According to legend, in Guqiong, there lived a loving couple. Later, when his wife died, the husband felt very lonely and secretly prayed that he could ascend to heaven as soon as possible so that he could meet his wife. After her husband died, the crane really took him to heaven and became a morning glory. Unfortunately, the husband and wife are separated by the Tianhe River, one in the east and the other in the west, so they can't meet at ordinary times. Heavenly Emperor was deeply moved by them, and let them cross the bridge built by magpies on the seventh day of July every year. This is what people often say when the Cowherd and the Weaver Girl meet at the Magpie Bridge. In ancient Greek and Roman mythology, Vega was called "Lula" and "Lila", meaning harp. [Lila] hence the name. Vega's diameter is 3.2 times that of the sun, its volume is 33 times that of the sun, and its surface temperature is 8900 degrees Celsius, showing a bluish white color. It is one of the three brightest stars in the northern hemisphere sky, about 26 light years away from the earth. More than 654.38+300,000 years ago, Vega was once the North Star. Due to the precession of the earth's axis, the current Polaris is Xiaoxiong-Alpha. But in 6.5438+0.2 million years, Vega will return to the prominent position of Polaris. Next to Vega, four of them formed a small diamond. Legend has it that this small diamond is a shuttle used by the weaver girl to weave cloth. While weaving, the Weaver Girl looked up at the Altair (Hegu II, Eagle-α) and her two sons (Hegu I and Hegu III) on the east bank of the Milky Way. Modern astronomical observations show that the entire solar system is moving towards Vega at a speed of 19 km per second. Far away from Vega is He Gu Er, a first-class bright star on the east bank of the Milky Way, whose scientific name is Aquila-α, commonly known as Altair. Like Vega, it is a very famous bright star in the summer night sky. Altair is about 16 light-years away from the earth, its diameter is10.6 times that of the sun, its surface temperature is about 7000 degrees, it is silvery white, and its luminous power is 8 times greater than that of the sun. Altair rotates very fast, about 7 hours, so its shape is oblate. It is calculated that its equatorial radius is 0.5 times of 65438+ polar radius. There is a dark star on each side of Altair, which is called Hegu I and Hegu III respectively. Together with Hegu II, it is called "Hegu Samsung". The river drum is like a long shoulder pole, so people call it "the shoulder pole star". Legend has it that Cowherd (Hegu II) is in the middle of the pole, carrying his two sons Hegu I and Hegu III at both ends, and has been chasing the Weaver Girl. In the summer sky, three bright stars, Altair, Vega and Tianjin IV, Cygnus-α, form an eye-catching triangle, which is called "Summer Triangle". Altair is located at the southern end of the triangle. This big triangle is an important manifestation of finding summer constellations. In the middle of the night in late summer, the triangle and its nearby galaxies rose to the zenith. In the middle of summer and autumn, Altair and Vega are high in the sky, which is a good season to observe them.

Altair (Altair)

Altair

Hegu II is the alpha star of Aquila, commonly known as "Altair". It is a very famous bright star in the sky in summer and autumn, and it is silvery white. It is 16.7 light years away from the earth, with a diameter of10.6 times that of the sun, a surface temperature of about 7000℃, and its luminous power is 8 times greater than that of the sun. It faces Vega across the Milky Way. According to an ancient legend, the Cowherd and the Weaver Girl met at the Magpie Bridge on July 7th. In fact, the Cowherd and the Weaver Girl are 14 light years apart. Even on the most powerful rocket in modern times, they never met after hundreds of years. The two dark stars on both sides of Altair are Altair's two sons-Heguyi and Heguyi. Legend has it that Cowherd and his two sons chased Weaver Girl on a pole.