Moon and the Lion

The Moon slides between two of the brighter stars of Leo tonight. They all climb into good view in mid-evening. Regulus, the lion’s brightest star, will stand to the lower right of the Moon. And Algieba, the third-brightest, will be about the same distance to the lower left. The Moon will pass between them during the night.

It’ll actually pass much closer to a third member of the constellation, Eta Leonis. The star is a good bit fainter than the other two, so it’s harder to see through the Moon’s glare. But the Moon will pass within about a degree of it — half the width of your finger held at arm’s length.

Eta Leonis looks fainter than Regulus and Algieba mainly because it’s almost 1300 light-years away — hundreds of light-years farther than the other two.

The star is big, bright, heavy, and hot — about 10 times as massive as the Sun, and perhaps 20,000 times brighter. It’s so heavy that it’s likely to end its life as a supernova — a titanic explosion that’ll rip the star to bits. Only its dead core will remain — probably a neutron star — a superdense ball more massive than the Sun but only a few miles across.

There are hints that Eta Leonis might have one or more companion stars. So far, though, astronomers haven’t been able to confirm any of them.

Watch as the Moon slides just past Eta Leonis during the night. Binoculars will help you pick out this impressive but tough-to-see star.
 

Script by Damond Benningfield