Looking Up: Will Work For Helium

Jun 4, 2018

Credit Till Credner, AlltheSky.com / wikipedia

This week on Looking Up we comb through Leo the Lion's mane and discover a star by the name of Algenubi. 

We’ve talked before about constellations that really don’t look like what they’re named after, and some that do. The constellation Leo falls into that second group, as the bright star Regulus anchors the neck, so to speak, of the lion, with five stars above making what looks like a backwards question mark, or more correctly, the head and mane of the lion. And the very last star in that mane, out at the end, is the very cool star with a very long name, Al Ras Al Asad Al Janubiyyah, known today simply as Algenubi.

About 250 light years away, Algenubi is a bright giant star that sends off into space over 360 times as much light as our Sun, even though it is actually a touch cooler, at only about 9800℉. How does it manage to be so much brighter? Well, it’s larger, at least 23 times bigger across, and it also not as dense, so it only weighs four times what our Sun weights. Algenubi takes about 200 Earth days to rotate once, far slower than our Sun’s roughly 27 Earth days.

It’s also doomed! Algenubi started off life only about 165 million years ago as a super-hot baby, and it’s burned through all it’s helium. Our Sun, by comparison, is about 4.6 billion years old, and has about 5 billion years of fuel left. So pity poor Algenubi, it gorged itself and now will quickly become a Red Giant star and then, poof!

If you’d like to take a closer look at Algenubi or any of the other wonderful and amazing things in the sky, please visit csastro.org for a link to information on our monthly meetings and our free public star parties.