Starwatch: the lion in spring

The constellation Leo dominates the southern sky, with Regulus its brightest star

Starwatch 23 April 2018 Leo

One of the most prominent constellations in the spring sky is Leo. During the winter, it has climbed out of the eastern sky and now dominates the south. The constellation is one of the oldest to be recognised in its current form. The Mesopotamians recognised this grouping of stars about 4,000 years ago.

Its brightest star is blue-white Regulus, which forms the front of the lion’s body. Lying 79 light years away, Regulus is a multiple star system. It consists of at least four stars although these are impossible to separate with the naked eye.

The rest of the stars that make up the constellation are dimmer but still easy to pick out by eye. Denebola, which derives from an arabic phrase meaning lion’s tail marks the animal’s rear end. It is a blue-white star almost twice the diameter of the sun. Algenubi marks the head and is a yellow giant star, about 23 times sun’s diameter.