How often do you gaze into the starry dome above your head? Do you know which is the brightest star in the sky? Perhaps, most of the modern generation of our country is not at all familiar with the location of the star luminaries in the firmament. Astronomy is no longer a compulsory subject in educational institutions, and the number of students interested in it is steadily decreasing due to the constant development of information technologies. But the stars and celestial bodies, as a rule, are interested in in childhood! However, even among the romantics there are those who want to get acquainted with the largest stars, planets and the arrangement of constellations.
The sun, in fact, is a star, but it makes no sense to consider it the brightest star. The brightest star in the sky is Sirius, located in the constellation Canis Major. It is best seen in winter in the Northern Hemisphere. But why is Sirius brighter than other stars in the sky?
This is due to the close location of Sirius to the Sun - 8.6 light years. In addition, Sirius is 22 times luminous than the Sun. But this figure is not considered a record among the stars. It is thanks to the good luminosity and close location of Sirius in the constellation Canis Major that became the brightest star in the sky.
In addition, Sirius is a binary star. Sirius A and Sirius B revolve around the common center of mass, the latter of which is recognized as a white dwarf with an ultrahigh mass and is “living out” its stellar term.
A measure of the brightness of a celestial body is defined by the term "apparent magnitude". In fact, the smaller the apparent magnitude, the brighter the celestial body. So, for Sirius it is –1.46, and for the Sun –26.72. Three more brightest celestial bodies have a "minus" stellar apparent magnitude - the star Canopus in the constellation Carina (–0.72), Alpha Centauri (–0.27) and Arcturus in the constellation Bootes (–0.05).
The brightest star in the sky has long been given a mystical character. In ancient Egypt, she was worshiped as the goddess Sopdet, and in Sumerian-Akkadian astronomy she was personified with the god Ninurta and called "Arrow". According to Sirius, the ancient Egyptian priests predicted the flooding of the Nile.
Translated from Greek, the brightest star in the night sky means "brilliant", "bright", but in ancient times it was called the "Dog Star". According to Greek mythology, the dog Orion (a constellation not far from Canis Major) became the star Sirius.
Undoubtedly, the distance to our planet directly affects the brightness of a star in the sky. If the hypergiant "UY", located in the constellation of the Shield, was a little closer to the Sun, then Sirius would have lost the status of the brightest star. The UY Shield star holds the status of the largest known star. Its radius is 1708 times greater than the radius of the Sun, and its diameter is 2.4 billion kilometers.
If you decide to look at Sirius, go outside on a winter night and look at the sky in a southerly direction. By mentally drawing a line along Orion's belt to the left, you can easily find the brightest star, which is sometimes visible even during daylight hours. True, to see it, you will need to wait until sunset.
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