Enter the radius and temperature of a start into the calculator to determine it’s luminosity.

## Luminosity Formula

The following formula is used to calculate the luminosity of a star.

L = 4 * pi * R^{2} * SB * T^{4}

- Where L is the luminosity
- R is the radius of the star (m)
- SB is the stefan-boltzmann constant (5.670*10
^{-8}W*m^{-2}* K^{-4}) - T is the temperature (K)

## Luminosity Definition

Luminosity is defined as the radiant energy or power given off by a star.

## Luminosity Example

How to calculate luminosity?

**First, determine the radius.**Calculate the radius of the start.

**Next, determine the temperature.**Calculate the surface temperature of the star.

**Finally, calculate the luminosity.**Calculate the luminosity of the star using the equation above.

## FAQ

**What is luminosity?**

Luminosity is a measure of the radiant power given off by an object. This object is most often a start or large celestial body.

**What is radiant power?**

Radiant power is the total energy emitted by light producing object through radiant flux.