Ursa Major moving group

Based on the numbers of its constituent stars, the Ursa Major Moving Group is believed to have once been an open cluster, having formed from a protostellar nebula approximately 500 million years ago.

Some of the brighter stream members include Alpha Coronae Borealis (α CrB or Alphecca or Gemma), Beta Aurigae (β Aur), Delta Aquarii (δ Aqr), Gamma Leporis (γ Lep) and Beta Serpentis (β Ser).

There is also a "stream" of stars which are likely members of the Ursa Major Moving Group, scattered more widely across the sky (from Cepheus to Triangulum Australe).

The bright, nearby star Sirius was long believed to be a member of the group, but may not be, according to research in 2003 by Jeremy King et al. at Clemson University.

The Sun drifted in along its 250-million-year galactic orbit, and 40 million years ago was not near the Ursa Major group.

Early illustration showing how many of the stars in Ursa Major move in a group
Map of stars and open clusters within 100 parsecs of the Sun. The Ursa moving group is near the center at 120° galactic longitude .