Merak is this Month's Star

This month look for the star Merak in Ursa Major. The popular name of Ursa Major is the Big Dipper. Actually, the Big Dipper is an asterism, or familiar pattern of stars and not a constellation. The Big Dipper asterism represents a bear’s hind quarters and extremely long tail. The rest of the bear consists of fainter stars, which gives Ursa Major its ursine shape. The constellation’s name means Great Bear in Latin.

Astronomers call Merak Beta Ursae Majoris. In Arabic, Merak means “flank of the bear”. Merak is a star larger star than our sun; it’s three times more massive and 60 times brighter. Its extra mass squeezes the star’s core with such great force that it’s fusing its hydrogen fuel faster than does the sun. Merak’s greater fusion rate makes it a white hot star with a surface temperature of over 15,000 degrees. Merak is 79 light years away, so the light you see tonight left the star in 1936.

You’ll find Merak and Ursa Major high overhead after it gets dark in April. The dipper is upside down and appears to be pouring the water in its bowl into the Little Dipper.