Double Cluster

The Double Cluster, is NGC 884 and NGC 869, a group of two open star clusters in the Perseus constellation. It has many blue and red stars.

Both are visible with the naked eye. NGC 869 and NGC 884 lie at a distance of 7,500 light years. That is relatively close-by (the Milky Way galaxy has a diameter of roughly 100,000 light years.)

Stars
RS Persei and T Persei
These are two red supergiant stars in the star cluster. They are 770 and 510 times larger than the Sun respectively.
SU Persei and AV Persei
These are also red supergiant stars. They both are 780 and 770 times larger than the Sun respectively.
S Persei
A red hypergiant 1,212 times larger than the Sun.Thompson, R. R.; Creech-Eakman, M. J. (2003). "Interferometric observations of the supergiant S Persei: Evidence for axial symmetry and the warm molecular layer". American Astronomical Society Meeting 203 203: 49.07.

References

Category:Star clusters