Messier 67 is an open star cluster located in the constellation of Cancer. It is approximately 2,700 light-years away from Earth and contains around 100 stars. The cluster is estimated to be about 4 billion years old, making it one of the oldest known open clusters. The stars in Messier 67 are relatively similar in age and composition, which allows astronomers to study stellar evolution. The cluster is also notable for its abundance of binary star systems, where two stars orbit each other. This makes it an interesting target for research in stellar dynamics and formation.