Star Colour-Temperature RechnerFormel

## Star Colour and Temperature

A star's colour is determined by its surface temperature. Hotter stars appear blue-white; cooler stars appear orange-red.

### Peak Wavelength (Wien's Law)

**lambda_max = 2.8978e6 / T** (nm)

### Approximate B-V from Temperature

**B-V ≈ -3.684 log10(T) + 14.551**

This empirical fit works reasonably for main-sequence stars between 3000 and 30 000 K.

Lösungsbeispiel

A blue star at 10 000 K.

  1. Peak = 2 897 800 / 10000 = 289.8 nm (ultraviolet)
  2. B-V ≈ -3.684 × log10(10000) + 14.551
  3. = -3.684 × 4 + 14.551 = -0.185
  4. Negative B-V: more blue than visual light, appears blue-white.