StarDate

Jumpy Stars


Listen Later

The celestial great bear is light on his feet. His paws are represented by three pairs of stars. And all three pairs have names that mean “leap” or “spring.”

The stars of the bear’s hind leg are known as Alula Borealis and Alula Australis. “Alula” is from an Arabic phrase that means “the first leap of the gazelle.” The other pairs of stars represent the second and third leaps.

Alula Borealis — the northern member of the pair — is the brighter of the two stars. It’s a giant star that’s passed the end of its “normal” lifetime. It’s going through a series of changes in its core. Those changes have caused the star’s outer layers to puff up like a giant balloon. The star is almost 60 times the Sun’s diameter, and almost 800 times its total brightness. That makes it easy to see even though it’s 400 light-years away.

Alula Australis — the southern star — is only about 30 light-years away. It actually consists of four stars, which are split into two pairs. The leading light of each pair is similar to the Sun. The two companion stars are much smaller and fainter than the Sun, so they don’t add much to the system’s brightness.

Alula Borealis and Australis are bright enough to see with the unaided eye, although not from light-polluted cities. At nightfall, they’re well to the right of the bowl of the Big Dipper — the bear’s body. They’ll rotate high above the dipper during the night, and stand to its lower left at first light tomorrow.


Script by Damond Benningfield

...more
View all episodesView all episodes
Download on the App Store

StarDateBy Billy Henry

  • 4.6
  • 4.6
  • 4.6
  • 4.6
  • 4.6

4.6

251 ratings


More shows like StarDate

View all
Radiolab by WNYC Studios

Radiolab

43,891 Listeners

The 365 Days of Astronomy by 365DaysOfAstronomy.org

The 365 Days of Astronomy

349 Listeners

Planetary Radio: Space Exploration, Astronomy and Science by The Planetary Society

Planetary Radio: Space Exploration, Astronomy and Science

1,350 Listeners

SpaceTime with Stuart Gary by Stuart Gary

SpaceTime with Stuart Gary

323 Listeners

BirdNote Daily by BirdNote

BirdNote Daily

1,257 Listeners

Ask a Spaceman! by Paul M. Sutter

Ask a Spaceman!

836 Listeners

Astronomy Cast by Fraser Cain and Dr. Pamela Gay

Astronomy Cast

2,883 Listeners

Universe Today Podcast by Fraser Cain

Universe Today Podcast

570 Listeners

Space Nuts: Astronomy Insights & Cosmic Discoveries by Professor Fred Watson and Andrew Dunkley

Space Nuts: Astronomy Insights & Cosmic Discoveries

233 Listeners

Science Friday by Science Friday and WNYC Studios

Science Friday

6,440 Listeners

Short Wave by NPR

Short Wave

6,563 Listeners

The Supermassive Podcast by The Royal Astronomical Society

The Supermassive Podcast

330 Listeners

NASA's Curious Universe by National Aeronautics and Space Administration (NASA)

NASA's Curious Universe

887 Listeners

Why This Universe? by Dan Hooper, Shalma Wegsman

Why This Universe?

381 Listeners

Crash Course Pods: The Universe by Crash Course Pods, Complexly

Crash Course Pods: The Universe

572 Listeners