* Apparent brightness: This is how bright a star appears to us from Earth. The star with the greatest apparent brightness is Sirius, also known as the Dog Star.

* Absolute brightness: This is the actual amount of light a star emits, regardless of its distance from Earth. The star with the greatest absolute brightness is VY Canis Majoris, a red hypergiant star that is much larger than our Sun.

So, the answer depends on whether you're asking about how bright a star appears to us or how much light it actually produces.