The Hertzsprung-Russell Diagram (HR Diagram) is a plot of stars' luminosity (brightness) against their temperature. While the HR Diagram doesn't directly provide a numerical value for the Sun's luminosity, it helps us locate the Sun's position on the diagram.

The Sun is a main sequence star with a spectral type of G2V. This means it falls within a specific region on the HR Diagram, where stars of similar temperature and luminosity reside.

Based on the Sun's position on the HR Diagram, we know it has a luminosity of 1 solar luminosity, which is defined as the luminosity of our own Sun.

In absolute terms, the Sun's luminosity is approximately 3.828 x 10^26 watts.