Since they only exist for a short time, they are rare:

Blue dwarfs are often the child stage of a later giant. In a few million years, they fuse all the hydrogen in their interior into helium – a rather short life span for a star. Therefore they glow in blue and ultraviolet light – they belong to spectral type O. But their large mass creates enormous pressure in the core, which accelerates nuclear fusion.īlue dwarfs burn up quickly, developing high surface temperatures. Thus they resemble blue giants but are not as large as these. They reach fifty solar masses and shine 10,000 times brighter than our sun. Blue Dwarfsīlue dwarfs are the largest, brightest and hottest main sequence stars, top left in the Hertzsprung-Russell diagram. The star expands into a gigantic giant or supergiant, and helium or heavier elements are fused inside. But when the hydrogen in the core runs out, the quiet star existence is over: The star is very stable and shines with constant brightness and colour. In the evolution of a star, its existence as a main-sequence star is the long, stable resting phase of hydrogen burning: in the core of the star, hydrogen atoms are fused to helium by enormous pressure and heat. This branch reaches from the red, faint M-stars – the red dwarfs – over the yellow dwarfs to the bright, blue shining and very hot O-stars – the blue dwarfs. Because they form the sharply defined main branch in the Hertzsprung-Russell diagram, they are called main-sequence stars. Thus they are rather faint stars of luminosity class V. Over 90 per cent of all stars are dwarf stars – (like our sun): Their diameters range from 0.1 to 25 solar diameters, they have 0.07 to 50 solar masses, and their luminosity ranges from -6 mag to 16 mag absolute brightness.

Name a blue main sequence star