Free · Physics models
Stellar Luminosity and Bolometric Magnitude
Estimate stellar luminosity and bolometric magnitude from radius, temperature and distance.
- Formula & worked example
- Private in your browser
- No signup
Calculator inputs
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How to use this calculator
- Enter the known values in the units shown. Results update as you type.
- Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
- Use the worked example to check the method. Reset restores the starting fields.
Private by default
Inputs and results stay in this browser tab. Bookify does not upload or store the values you enter.
Formula and method
Luminosity = 1.0000000; Absolute magnitude = 4.7399959; Apparent magnitude = 4.7399959. The worked example lists its inputs and unit conventions.
L/Lsun = (R/695700 km)²(T/5778 K)⁴; Mbol = −2.5 log₁₀(L/3.0128×10²⁸ W).
Worked example
Enter these known values and leave the other values blank.
- Star radius
- 1 R☉
- Star temperature
- 5778 K
- Distance
- 10 pcs
- Luminosity
- 1 L☉
- Absolute magnitude
- 4.74
- Apparent magnitude
- 4.74
Assumptions and limitations
- This is a historical 5778 K solar-temperature normalization, with nominal solar luminosity 3.828×10²⁶ W and radius 695700 km. It is an approximate stellar model rather than exact Stefan–Boltzmann radiometry. Magnitudes are bolometric; extinction, bandpass and lensing corrections are omitted. The parsec selector retains rounded 3.0857×10¹⁶ m.
- Clear the unknown quantity to solve a supported inverse. Keep known quantities fixed with locks. A zero multiplier can make an inverse underdetermined.
Common questions
What assumptions apply?
This is a historical 5778 K solar-temperature normalization, with nominal solar luminosity 3.828×10²⁶ W and radius 695700 km. It is an approximate stellar model rather than exact Stefan–Boltzmann radiometry. Magnitudes are bolometric; extinction, bandpass and lensing corrections are omitted. The parsec selector retains rounded 3.0857×10¹⁶ m.
How do inverse controls work?
Clear the unknown and enter enough independent known values. Locks retain known quantities; singular or impossible inverses may remain incomplete.
References
This is a historical 5778 K solar-temperature normalization, with nominal solar luminosity 3.828×10²⁶ W and radius 695700 km. It is an approximate stellar model rather than exact Stefan–Boltzmann radiometry. Magnitudes are bolometric; extinction, bandpass and lensing corrections are omitted. The parsec selector retains rounded 3.0857×10¹⁶ m.