Ursa Major moving group

The Ursa Major Moving Group, also known as Collinder 285 and the Ursa Major association, is a special group of stars that move together through space. These stars share similar speeds and directions, which suggests they all came from the same place and time long ago. In fact, the stars in this group formed about 300 million years ago.

The core of the Ursa Major Moving Group is located roughly 80 light years away from us, sitting inside an area of space called the Local Bubble. What makes this group particularly interesting is that it includes many bright and well-known stars, especially most of the stars that make up the famous Big Dipper pattern in the night sky.

Because these stars are close to Earth and easy to see, the Ursa Major Moving Group helps scientists study how stars form and move over time. By watching these stars, researchers can learn more about the history of our part of the galaxy and the processes that create new stars.

Discovery and constituents

All the stars in the Ursa Major Moving Group travel through space in nearly the same direction at similar speeds. They also share similar chemical makeup and age, which tells astronomers they likely came from the same place long ago.

This group of stars was discovered in 1869 by Richard A. Proctor. He noticed that most stars in the Big Dipper—all except Dubhe and Alkaid—all move toward the same spot in the sky, showing they are related. The Ursa Major Moving Group may have started as an open cluster, forming from a cloud of gas about 500 million years ago. Today, its center lies about 80 light-years from Earth, making it the closest group of stars like a cluster to our planet.

Some well-known stars in this group include Alpha Coronae Borealis, Beta Aurigae, Delta Aquarii, Gamma Leporis, and Beta Serpentis.

Proper motions visualised