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Calcimator

Stellar Luminosity Calculator

Calculate stellar luminosity using Stefan-Boltzmann law. Find absolute magnitude, main sequence lifetime, and stellar parameters.

Inputs

Solar Radii
K
Solar Masses

Results

Luminosity

1.004 Solar Luminosities

Absolute Magnitude

4.83

Main Sequence Lifetime

10,000,000,000 billion years

Apparent Magnitude4.83
Surface Flux63,200,699.73 W/m²
How to Use This Calculator
  1. Enter Stellar Radius (solar radii) — the Sun is 1 R☉; giants like Betelgeuse exceed 1,000 R☉.
  2. Enter Surface Temperature (K) from spectral classification: O stars >30,000 K, G stars ~5,000–6,000 K, M stars <3,500 K.
  3. Enter Stellar Mass (solar masses) to compute the Main Sequence Lifetime via the mass-luminosity relation.
  4. Read Luminosity (solar luminosities) and Absolute Magnitude to compare with catalog values.
  5. Use Main Sequence Lifetime (billion years) to understand how much longer the star will remain hydrogen-burning.

How the result changes with Surface Temperature

Surface TemperatureLuminosityAbsolute MagnitudeMain Sequence Lifetime
10,90012.717 Solar Luminosities2.0710,000,000,000 billion years
35,6501,455.231 Solar Luminosities-3.0810,000,000,000 billion years
65,35016,431.456 Solar Luminosities-5.7110,000,000,000 billion years
90,10059,373.526 Solar Luminosities-7.110,000,000,000 billion years

What each input means

Stellar Radius
Radius of the star
Surface Temperature
Effective surface temperature in Kelvin
Stellar Mass
Mass of the star

How this is calculated

Formula

L = 4πR²σT⁴ (Stefan-Boltzmann Law)

Worked example, using the default values

  1. Identify Input Parameters
    Stellar Radius = 1, Surface Temperature = 5778, Stellar Mass = 1 = 3 input(s) provided
  2. Calculate Luminosity
    Luminosity
    1.004 = 1.004
  3. Calculate Absolute Magnitude
    Absolute Magnitude
    4.83 = 4.83
  4. Calculate Main Sequence Lifetime
    Main Sequence Lifetime
    10000000000 = 10000000000
  5. Calculate Apparent Magnitude
    Apparent Magnitude
    4.83 = 4.83
  6. Calculate Surface Flux
    Surface Flux
    63200699.73 = 63200699.73

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