Columba

A faint dove sails low across the sky on February evenings. It’s due south as night falls now. But it’s so low that you need to be pretty far south to see it.

Columba is a recent constellation. Dutch mapmaker Petrus Plancius created it in the late 16th century. He carved it from a region with almost no bright stars. He called it Columba Noachis — Noah’s Dove. It represented the dove released from Noah’s Ark at the end of the biblical flood.

The dove’s brightest star is Alpha Columbae. It’s bright enough to see with the unaided eye, even though it’s about 260 light-years away. That means it really is bright — more than a thousand times brighter than the Sun.

The star is also much bigger and heavier than the Sun. And it’s spinning much faster than the Sun does. As a result, it’s flinging hot gas from its surface out into space. As that material cools, atoms link up to form solid particles, encircling the star in a cloud of dust.

Models of how stars evolve suggest Alpha Columbae is less than a hundred million years old — just a couple of percent the age of the Sun. Because of its great mass, though, it’s aging much faster than the Sun. That means it’s almost half way through the prime of life, when it steadily “fuses” hydrogen in its core to make helium. At the end of that phase, it’ll puff up to giant proportions and shine much brighter than it does now — making the dove much more prominent.

More about Columba tomorrow.
 

Script by Damond Benningfield