Which star is the brightest in the universe?

The brightest object in the universe should be a star.

The star is one of the most basic celestial bodies in the universe, and it is a spherical celestial body composed of hydrogen, helium and other elements. Its core is high temperature and high pressure, which can produce nuclear fusion reaction and release huge energy. These energies radiate in the form of light and heat, making the stars shine brilliantly in the universe.

The brightness of a star depends on its size, mass and temperature. According to the brightness grading standard of stars, we can divide stars into seven grades, from the brightest to the darkest: 0, Ia, Ib, II, III, IV and V respectively.

Level 0 is called supernova, which is an extremely bright celestial body, but their existence time is very short, usually ranging from a few days to several months, so they are not regarded as stars. At present, the brightest star is Supergiant star in Andromeda, which is about 5,000 light years away from the Earth.

The mass of VY Canis Majoris about 30 times that of the sun, and its radius is 1700 times that of the sun. It is one of the largest stars known at present. Its brightness is more than 500 thousand times that of the sun, and even if it is so far away from the earth, its light can shine in the sky.

Normative naming

1603, the German astronomer John Bayer created a Bayer nomenclature, which combined the Greek alphabet sequence with the constellation and named each star in the constellation. Then john flamsteed, a British astronomer, invented the Franster nomenclature based on the right ascension. Bayer nomenclature is named in Greek alphabetical order according to the brightness of each star in the constellation.

For example, Sirius is the first bright star in Canis, so it is called Canis Alpha, Vega is Lyra Alpha, and Betelgeuse is Orion Beta. When you run out of Greek letters, use numbers or Roman letters. Fransted, on the other hand, sorts the stars according to the right ascension, and only numbers the stars that can be seen in the northern hemisphere.

Another naming method of stars is catalog naming, which is compiled by astronomers according to the observation data system. Such as Bonn catalog, HD catalog, Ebba catalog, SAO catalog, variable catalog, nebula and cluster star catalog, messier catalog and Orwell's basic catalog and so on.

They classify different stars (or galaxies) and sit in appropriate positions, and their contents are fine and there are many stars, which greatly facilitates the study of astronomy.

Above content reference: Baidu Encyclopedia-Star