Stellar Flux Calculator Formula

Understand the math behind the stellar flux calculator. Each variable explained with a worked example.

Formulas Used

Observed Flux

flux = luminosity / (4 * pi * pow(distance, 2))

Variables

VariableDescriptionDefault
luminosityLuminosity(W)3.828e+26
distanceDistance(m)149600000000

How It Works

Stellar Flux

Flux is the power received per unit area at a given distance from a luminous source.

Inverse-Square Law

F = L / (4π d²)

As distance doubles, flux drops to one-quarter.

Worked Example

Solar flux at 1 AU.

luminosity = 3.828e+26distance = 149600000000
  1. 01F = L / (4π d²)
  2. 024π d² = 4π × (1.496e11)² = 2.812e23
  3. 03F = 3.828e26 / 2.812e23 ≈ 1361 W/m²

Ready to run the numbers?

Open Stellar Flux Calculator