Night Sky Star Size

[JonStar]

The stars that are visible by eye - - is it safe to say that almost all of them are larger than our sun?

[Ann]

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Alpha+Beta with Proxima Centauri

Of the stars you can see in the sky with your naked eye, about 99% of them are brighter (and also larger) than the Sun.

However, about 95% of all the stars in the Milky Way are fainter and also smaller than our Sun. We don't see them with our naked eyes simply because they are so faint.

The nearest stellar neighbour that we know of, Alpha Centauri, is a triple system. Alpha Centauri A is just a little bit larger and brighter than the Sun, and Alpha Centauri B is a bit smaller and fainter than the Sun. Even though these two stars are not fantastically bright by any means, their nearness makes them the third brightest-looking star in the sky. But the third component of this triple system, Proxima Centauri, which is currently closer to us than any known star in the universe (except the Sun), is so faint that you can't possibly see it without a telescope.

http://stars.astro.illinois.edu/sow/rigil-kent.html wrote:
As a mid-class M (M5.5) dwarf star, Proxima is faint indeed, to the eye 18,000 times dimmer than the Sun. From Alpha Cen proper, Proxima would appear as only fourth magnitude, about as bright as the faint stars of the Little Dipper appear to us. When infrared radiation produced by its 3040 Kelvin surface is accounted for, it is seen to be more luminous, but still only 1/600 as bright as the Sun (and 15 percent the size), the result of a mass only 12 percent solar.

Ann