Double cluster
As double cluster two closely adjacent to Open clusters designated. Most often the word is used for the two bright star clusters h and χ Persei in our galaxy , which can already be seen with clear eyes as blurred nebulae in the constellation Perseus .
They each have a diameter of 0.5 ° and the brightness is fifth or sixth magnitude. Although known since antiquity, they are not included in the Messier catalog ; in the New General Catalog they have the numbers NGC 884 and NGC 869 . Both are comparatively young star formation regions, which may have arisen from a common huge molecular cloud.
There are even two bright double star clusters in our neighboring galaxy, the Large Magellanic Cloud . The better known is called Hodge 301 after its discoverer . It emerged from a gas cloud from the massive Tarantula Nebula and is considered to be one of the most active regions for recent star formation .
Individual evidence
- ↑ Michael Vogel: Which star is that? Kosmos, 2014, ISBN 978-3-440-14371-1 ( limited preview in Google Book Search).
- ↑ bibliotecapleyades.net: Open Cluster , accessed on August 18, 2018
- ↑ Stephen James O'Meara: Deep-Sky Companions: Hidden Treasures . Cambridge University Press, 2007, ISBN 978-1-139-46373-7 , pp. 132 ( limited preview in Google Book search).