As an expert in the field of astronomy, I can tell you that the brightest stars in the sky are typically those that are both intrinsically luminous and relatively close to Earth.

The blue supergiants are among the most luminous stars known, but they are not necessarily the brightest as seen from Earth because they are quite rare and few are close enough to be visible to the naked eye.

The red supergiants, on the other hand, can be both very luminous and relatively close to us, which makes some of them appear quite bright in our night sky. Betelgeuse, in the constellation of Orion, is an example of a red supergiant and is one of the brightest stars in the sky.

Another factor to consider is the spectral class of the star. O-type stars are very hot and emit a lot of their light in the ultraviolet range, which makes them extremely luminous but much of this light is not visible to the human eye.

For stars that are visible to the naked eye, the apparent brightness, or apparent magnitude, is also affected by the star's distance from Earth. The closer a star is, the brighter it appears to us, even if it's not as intrinsically luminous as a more distant star.

In summary, the brightest stars we can see are often red supergiants that are close to Earth, combined with a few other factors like their size, temperature, and the amount of light they emit in the visible spectrum.

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Dwarf stars are relatively small stars, up to 20 times larger than our sun and up to 20,000 times brighter. Our sun is a dwarf star. Yellow dwarfs are small, main sequence stars. The Sun is a yellow dwarf.read more >>