The star at the top of Leo’s head has lots of aliases. Its formal name is Algenubi – from a longer Arabic name that means “the southern star of the lion’s head.” But most astronomers call it by its “Bayer” name – Epsilon Leonis. That naming system was devised centuries ago, using letters of the Greek alphabet to indicate a star’s priority in its constellation – its brightness or position.
But Algenubi has several dozen other designations. Most of them are from catalogs compiled over the ages. Some of the catalogs highlight different forms of energy, such as radio waves or X-rays. Others classify stars based on their temperature or composition. And some are observing lists for space telescopes.
Algenubi is a class “G” star, indicating that its surface is about the same temperature as the Sun’s. But the Sun is a “dwarf” star, which means it’s in the prime of life. Algenubi, on the other hand, is a giant or sub-giant. It’s puffed up to more than 20 times the Sun’s diameter. That’s made it a few hundred times brighter than the Sun, so it’s easily visible from about 230 light-years away – one of Leo’s most remote bright stars.
Leo stretches high across the east and southeast in early evening. Look for its brightest star, Regulus. Leo’s head and mane form a backward question mark to the upper left of Regulus. Algenubi is at the outer point of the question mark – a bright star with many names.
Script by Damond Benningfield