- Luminosity is just the intrinsic brightness of a star.

- The two stars in the previous example might have different magnitudes, but the same luminosity.

- If we know a star's magnitude and its distance, we can figure out its luminosity.

- Measured in units of Solar Luminosity.

Examples:

  Deneb: Luminosity of 250,000

  The Sun: Luminosity of 1

  Proxima Centauri: Luminosity of 0.000138