The classification of stars based on their spectral characteristics such as temperature and colour.

For example:
Class O stars, temp >=30,000 K, colour = blue
Class B stars, temp 10,000K to 30,000K, colour = blue white
Class A stars, temp 7,500K to 10,000K, colour = white
Class F stars, temp 6,000K to 7,500K, colour = yellow white
Class G stars, temp 5,200K to 6,000K, colour = yellow
Class K stars, temp 3,700K to 5,200K, colour = orange
Class M stars, temp 2,400K to 3,700K, colour = red

A Hertzsprung-Russell diagram displays spectral class against absolute magnitude (credit:- ESA)

Glossary A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Sky Highlights - April 2017

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Current Moon Phase



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