There have been more than one thousand planets confirmed outside our Solar System, but only a few are within star clusters.
Using the European Southern Observatory’s HARPS instrument, researchers have found three new planets in the star cluster Messier 67.
Of these three newly discovered planets, two have been found orbiting stars similar to the sun.
There are two main types of star clusters — open clusters and globular clusters.
An open cluster is a group of stars recently formed in a single cloud comprised of gas and dust.
Globular clusters are larger and older with the stars orbiting around the center of the galaxy.
Only six planets have been discovered in open clusters and none have been found in globular clusters.
Messier 67 is a star cluster located about 2,500 light-years from Earth in the constellation of Cancer. It contains around 500 stars.
In the Messier 67 star cluster the stars are all about the same age and composition as the Sun.