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Yellow Holmberg double

This system in the dwarf galaxy Holmberg IX has been identified as binary star of two yellow supergiants in early 2008. It was the first of this assumedly very rare kind to be discovered. The stars are merged together and therefore are peanut shaped. Their closeness could prevent an evolution towards a red supergiant. So this kind of star could be responsible for the very rare supernovae with yellow stars as progenitor.
As surprising as this discovery was, nevertheless a short while later a similar double has been discovered in the Small Magellanic Cloud.

Constellation: Ursa Major
Distance: 12 million light-years
Luminosity: 100 000 * Sun
Orbit period of the two stars: 271 days

Star A

Mass: 15 - 20 * Sun

Star B

Mass: 15 - 20 * Sun

Back: List of big and giant stars part 2


    Gelbes Holmberg-Doppel
Graphic: Kevin Gecsi, courtesy of Ohio State University.

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