Calculate the total power output of a star based on its radius and temperature.
Stellar Parameters
R_sun
K
Luminosity Results
Enter star radius and temperature
Quick Reference
RRadius of the star
TAbsolute temperature
σStefan-Boltzmann constant
L_sun3.828 × 10²⁶ W
Overview
Luminosity is the total amount of energy a star emits per unit of time. According to the Stefan-Boltzmann Law, luminosity depends on a star's surface area and the fourth power of its absolute temperature.
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Pro Tips
The Sun's surface temperature is about 5,778 Kelvin.
Luminosity L = 4 * π * R² * σ * T⁴.
Small changes in temperature lead to huge changes in luminosity because of the T⁴ factor.
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Fun Facts
"Wait, did you know that the most luminous star known, R136a1, is nearly 9 million times brighter than our Sun?"
"The term 'Luminosity' in astronomy specifically refers to power (Watts), while 'Apparent Magnitude' refers to how bright it looks from Earth."
"Red dwarves have very low luminosity and can live for trillions of years, while blue giants are extremely luminous but die in just a few million years."
