ONE FORMULA, ONE ANSWER
Eddington Luminosity Calculator
Calculate the spherical Eddington luminosity scale where radiative and gravitational acceleration balance. Choose input units and calculate one value within the stated conditions.
Inputs
Calculations run in this browser. Scientific notation such as 1.2e-3 is supported. Do not group thousands.
Result
Eddington force-balance luminosity L_Edd
Enter values and select Calculate.
L_Edd = 4πGMc/κ
Assumptions
Required: M,κ>0. κ is a constant effective mass opacity for radiation momentum transfer in m²/kg, not an absorption coefficient per length. Spherical symmetry, isotropic steady radiation, Newtonian gravity and matter-radiation coupling are assumed. The example κ=0.034 m²/kg represents electron scattering; composition and opacity are not inferred. Excluded: rotation, magnetic fields, beaming, convection and general relativity. This is not an absolute luminosity ceiling for every object.
Displayed values are floating-point approximations. Design safety factors and unprovided error contributions are not calculated.
Formula references and credits
NaNa Lab created the code, descriptions, icons and preview images. Text, figures and code from the linked references have not been reproduced.
Physical constants: NIST / CODATA 2022. The values of μ₀ and ε₀ are measured recommendations, not exact defining constants. Values and precision notes are in the source record.
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