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Starlight - Main Sequence - O - B - A - F - G - K - M - Luminosity Classes - Spectral Class Codes

Analysis of Starlight

The different colours of these stars
indicate their different temperatures.
They also have different luminosities.

These stars have similar temperatures,
but they vary in luminosity.

Our knowledge of the stars is gained by analysing starlight.

Colour indicates temperature. The hottest stars radiate at the blue end of the spectrum and the coolest at the red end.

The amount of light a star produces is called its luminosity. It depends upon the star's size and temperature. The brightest stars are millions of times more luminous than the dimmest.

These pages introduce the system astronomers use to classify stars and details some of the things astronomers have learned from the analysis of starlight.