W Большой Медведицы
This is a multiple star system. The two main components have apparent magnitudes of 10.08 and 12.70, and are separated by 0.50 arcseconds. The brighter component is a W Ursae Majoris variable eclipsing contact binary star system, whose two component stars share a common outer layer. Because the two components share their outer layers as the components of W Ursae Majoris do, they have the same stellar classification, and are classified as yellow F-type main sequence dwarfs. The components take 0.419822800 days (roughly 10 hours) to revolve around common barycentre. Orbital period variations would suggest the presence of additional perturbing objects, one of them likely substellar.