NGC 869 and NGC 884 - The Double Cluster (h Chi Persei)

The double clusters h and χ Persei, located in the constellation Perseus, are a stunning pair of open star clusters that have fascinated astronomers for centuries. These clusters, estimated to be around 14 million years old, are relatively young and packed with massive, luminous stars. Interestingly, both clusters exhibit only weak hydrogen alpha (Hα) emission, indicating that the more energetic, short-lived massive stars have already expelled much of the surrounding hydrogen gas through intense stellar winds and radiation. This reduced Hα emission suggests that the clusters are transitioning away from active star formation.

In addition, several rare carbon stars have been identified within the double clusters. Carbon stars are late-type, evolved stars rich in carbon, a product of fusion processes in their cores, which gives them a distinctive red hue. These stars add to the chemical diversity of h and χ Persei, and their presence highlights the clusters’ dynamic stellar evolution. Together, the faint Hα glow and unique population of carbon stars in h and χ Persei offer valuable insights into the lifecycle of massive star clusters and their chemical enrichment.

Photographed from Bamberg and Heidelberg, Germany under Bortle 5 conditions.