Source: wikibot/pismis-20
= Pismis 20
{wiki=Pismis_20}
Pismis 20 is an open cluster of stars located in the constellation of Cassiopeia. It is notable for being one of the most massive open clusters known, containing a significant number of stars, including a large population of massive, hot, and bright stars. The cluster is thought to be relatively young in astronomical terms, with an age of around a few million years.