the brightest-appearing star in the heavens. In the early 1800s, it was discovered that Sirius had a companion star that is so dense that 1 cubic inch of it has a mass of nearly 1 ton. The two stars revolve around each other so closely that at times it is hard to separate them by telescopic means. When they revolve closely, they exchange gas which flows between their equators. This causes the two stars to look like a dumbbell. —Games Congress Gls (Approved 13.8.92)