Drag the cross on the diagram (or use the sliders or arrow keys).
Drag the cross onto a dot to see which star it is. The instability strip is where stars that pulse in brightness (such as Cepheids) are found.
Find it
Click (or tap) the diagram. Keyboard: move the cross with the arrow keys, then press Enter.
The Sun's future
Press Play to follow the Sun's dot.
Simplified from published models. Watch the size panel: the Sun swells to over 200 times its width, then shrinks to about the size of Earth.
The star at the cross
Surface temperature
Spectral class
Luminosity (Sun = 1)
Absolute magnitude
Radius (Sun = 1)
Colour
Star at the cross
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Size compared with the Sun
Star positions are approximate published values. Radius uses L = R² × (T ÷ 5772 K)⁴; absolute magnitude uses M = 4.83 − 2.5 log L. Inspired by the University of Nebraska–Lincoln H–R Diagram Explorer. Made for kugelblitz.me Year 10 Science. Nothing you do here is saved or sent anywhere.