This oddball open star cluster in Cepheus is embedded within the emission nebula Sharpless 2–140.
The open cluster Pismis-Moreno 1 is involved with the emission nebula Sharpless 1-140, visible in this image made with the 4m Mayall Telescope at Kitt Peak National Observatory. Credit: KPNO
Here’s an oddball open star cluster I bet you’ve never seen — it’s catalogued as Pismis-Moreno 1. Lying at a high declination in the northern constellation Cepheus, it was discovered by Armenian-Mexican astronomer Paris Pismis and Mexican astronomer Marco Moreno-Corral.
Little data has been collected on this small group, which measures 9’ across and is involved with the emission nebula Sharpless 2–140, which surrounds it. The nebula and cluster lie approximately 3,000 light-years away.
The bright rim of the nebula is caused by ionization from the main sequence B star HD 211880, which is exciting a Bok globule.
This area is part of the so-called Cepheus Bubble, an expanding shell of gas and star formation associated with the Cepheus OB 2 Association.
