Labs / Astronomy
Blackbody Star Color
Every star glows as a blackbody, so its color is a thermometer. Drag the temperature slider (or grab a real star) and watch the disk change hue while the emission curve slides across the spectrum. The dashed marker is the peak wavelength & its color; the readouts track how hot, how blue, and how bright the star becomes.
T 5,778 Kλpeak 502 nmcolor yellow-whiteflux 63.2 MW/m²
What to try
- Why does a hotter star look blue while a cooler one glows red — isn't red the "hot" color on a stove?
- At what temperature does the peak wavelength leave the visible band and slip into the ultraviolet?
- The Sun peaks around 500 nm (green-ish). So why doesn't the Sun look green?
- Double a star's temperature. Does the flux double, or does Stefan-Boltzmann make it jump much more?
- Betelgeuse and Spica differ by a factor of about six in temperature — how differently do their curves and colors look?