There are billions of stars in the universe how are they classified

The stars are classified on the basis of their temperature and the spectra. Stars are divided into the 7 main classes.

Classification of stars:

The stars are classified on the basis of their temperature and the spectra. Stars are divided into the 7 main classes, O, B, A, F, G, K and M.

O-stars are the  hottest, bright and blue, while M-stars are dimmer, relatively cooler and red.

Therefore, the stars are classified on the basis of their temperature and the spectra.

To know more about Stars,

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In 1926, an astronomer named Edwin Hubble decided to classify the galaxies, grouping them according to some logical scheme.

Explanation:

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