A star luminosity is the total power it radiates in every direction, and the Stefan-Boltzmann law ties it neatly to just two things: how big the star is and how hot its surface is. Luminosity equals four pi times the radius squared, times the Stefan-Boltzmann constant, times the temperature to the fourth power. Because temperature enters as a fourth power, a modest rise in surface heat makes a star vastly brighter. This calculator takes the radius as a multiple of the Sun and the surface temperature in kelvin, then returns the luminosity in watts and in solar luminosities so you can compare it to our own star. Preset stars are one click away. It all computes in your browser.
A star luminosity is the total power it radiates in every direction, and the Stefan-Boltzmann law ties it neatly to just two things: how big the star is and how hot its surface is. Luminosity equals four pi times the radius squared, times the Stefan-Boltzmann constant, times the temperature to the fourth power.
Yes. Stellar Luminosity Calculator is completely free, with no sign-up and no usage limits.
Yes. Stellar Luminosity Calculator runs in any modern web browser. There is nothing to download or install.
Yes. Stellar Luminosity Calculator runs entirely on your device in your browser, so nothing you enter is uploaded to a server.