StarDate

Rastaban


Listen Later

The eyes of the dragon shine a third of the way up the northeastern sky at nightfall. Eltanin is the brightest star of Draco, with third-ranked Rastaban just above it. They circle high across the north during the night, and stand in the northwest at first light.

Although Eltanin looks brighter than Rastaban, that’s only because of their different distances. Eltanin is about 150 light-years away, while Rastaban is at 380 light-years. So if you lined them up side by side, Rastaban would shine about twice as bright as the dragon’s other eye.

Rastaban is only about 65 million years old, compared to four and a half billion years for the Sun. Yet it’s already passed the end of its “prime” lifetime.

That’s because it’s about six times as heavy as the Sun. Such massive stars “burn” through their nuclear fuel at a frantic rate. So Rastaban has already converted the hydrogen in its core to helium. Now, it’s probably getting ready to ignite the helium to make carbon and oxygen.

That’s caused the star to puff up – it’s about 40 times the diameter of the Sun. That’s the main reason it looks so bright – there’s a lot of surface area to beam light out into space.

Eventually, the nuclear reactions in the core will stop. The star’s outer layers will blow out into space. That will leave only the dead core – a cosmic ember as heavy as the Sun but only as big as Earth – closing one of the dragon’s bright eyes.

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

43,967 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

1,347 Listeners

SpaceTime with Stuart Gary by Stuart Gary

SpaceTime with Stuart Gary

325 Listeners

BirdNote Daily by BirdNote

BirdNote Daily

1,259 Listeners

Ask a Spaceman! by Paul M. Sutter

Ask a Spaceman!

836 Listeners

Astronomy Cast by Fraser Cain and Dr. Pamela Gay

Astronomy Cast

2,881 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

234 Listeners

Science Friday by Science Friday and WNYC Studios

Science Friday

6,464 Listeners

Short Wave by NPR

Short Wave

6,564 Listeners

The Supermassive Podcast by The Royal Astronomical Society

The Supermassive Podcast

331 Listeners

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

NASA's Curious Universe

886 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

571 Listeners