Wien Peak Wavelength
Calculator
Results
- Peak wavelength (nm)
- 502.039493
- Peak frequency (THz)
- 597.149152
- Peak photon energy (eV)
- 2.46961
Astronomy results
| Peak wavelength (nm) | 502.039493 |
| Peak frequency (THz) | 597.149152 |
| Peak photon energy (eV) | 2.46961 |
formula-map diagram
- Peak wavelength (nm)
- 502.039493
- Peak frequency (THz)
- 597.149152
- Peak photon energy (eV)
- 2.46961
Astronomical relationship
Formula
λ_max = b / T, b = 2.897771955 × 10⁻³ m·K= 502.03949324324
Note
This result is a simplified model: it applies the displayed textbook formula to the values you entered, assuming ideal spherical bodies, circular orbits, blackbody radiation and perfect optics, and ignoring atmospheric seeing, relativistic corrections beyond those stated, cosmological models and measurement uncertainty. Use published ephemerides and catalogue data for real observations.
More in Astronomy and space
See all →Frequently asked questions
What does Wien's law tell us about a star's color?+
Wien's law states that the wavelength at which a blackbody radiates most intensely is inversely proportional to its temperature: λ_max = b/T, where b is Wien's displacement constant (about 2.898×10⁻³ m·K). Hotter stars peak at shorter (bluer) wavelengths, and cooler stars peak at longer (redder) wavelengths.
Why does the Sun, at about 5,778 K, appear white or yellow rather than green?+
Wien's law puts the Sun's peak emission wavelength around 500 nm, which is indeed in the green part of the spectrum, but the Sun emits a broad range of wavelengths across the visible spectrum, and our eyes blend that combination into white or pale yellow. The peak wavelength tells you where emission is strongest, not the only color being emitted.
How is peak wavelength related to a star's actual surface temperature?+
Rearranging Wien's law gives T = b/λ_max, so measuring where a star's spectrum peaks lets astronomers calculate its surface temperature directly. This is one of the primary ways stellar temperatures are actually determined from telescope observations.
Why do very hot stars appear blue and very cool stars appear red?+
Extremely hot stars, above about 10,000 K, have peak wavelengths shifted into the ultraviolet, so the visible light we see skews toward blue. Cool stars, below about 3,500 K, peak in the infrared, so their visible emission skews toward red, which is why star colors form a continuous spectrum tied to temperature.
Does Wien's law apply to non-star objects too?+
Yes, it applies to any blackbody radiator, including planets, the cosmic microwave background, and even human bodies. The cosmic microwave background, at about 2.7 K, peaks in microwave wavelengths, exactly as Wien's law predicts for something that cold.