ONE FORMULA, ONE ANSWER
Exoplanet Transit Depth Calculator
Calculate the ideal fraction of stellar light blocked by an opaque planet fully within the stellar disk. 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
Stellar flux loss fraction δ
Enter values and select Calculate.
δ = (R_p/R_s)²
Assumptions
Required: 0≤R_p≤R_s and R_s>0. A uniformly bright circular star and an opaque circular planet with negligible emission are assumed. The whole planetary disk must lie inside the stellar disk during the evaluated phase. Excluded: grazing or partial overlap, limb darkening, atmosphere, reflected light, starspots and contaminating light. Orbital inclination and whether a transit occurs are not determined.
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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