Supergiant Stars

A state of stellar evolution beyond the main-sequence life of a star. A red giant core is degenerate ionized helium, surrounded by a shell of hydrogen fusion, that expands the outer atmosphere in response to higher core temperatures. The hydrogen fusing shell eats through the surrounding atmosphere and deposits helium onto the shrinking core. The ballooning atmosphere cools and glows red; hence red giant. The Sun will become a red giant the size of Earth's orbit in five to six billion years. Once the helium core reaches 100 million degrees, it explosively begins fusing helium. The birth of the active helium core is called the helium flash. The Sun as a red giant will fuse helium for about 2 billion years after the helium flash.

Radio Programs

Bright Paw The big dog’s brilliant paw Friday, February 13, 2015

Rigel The hunter’s complicated foot Monday, December 22, 2014

Even Brighter A couple of brilliant ways to die Wednesday, November 5, 2014

Brighter A bright star gets even brighter Tuesday, November 4, 2014

Sadr A case of stellar WYSIWYG Tuesday, October 14, 2014

Moon, Mars, and Antares Heating up the daytime sky Monday, September 29, 2014

Biggest of the Big The monsters of the Milky Way Tuesday, September 23, 2014

Sigma Scorpii Impressive stars near the scorpion’s heart Saturday, August 9, 2014

Moon and Antares Inflating a stellar supergiant Tuesday, August 5, 2014

Eta Carinae Building up to a big eruption Monday, June 16, 2014

Moon and Antares The amazing fate of a giant star Wednesday, June 11, 2014

Alnilam A bright buckle for the hunter’s belt Sunday, February 16, 2014

Wezen Dumping chemicals into space Wednesday, January 29, 2014

Mirzam Revving up a celestial dog Tuesday, January 28, 2014

M101 ULX-1 Weirdness in a nearby galaxy Thursday, January 16, 2014

More Aquarius A pair of yellow supergiants Sunday, December 8, 2013

Orion Rising Jumbo stars climb into view Friday, November 22, 2013

Megastars “Megastars” in a nearby galaxy Tuesday, July 9, 2013

Moon and Antares Evidence of ancient chemical factories Saturday, March 30, 2013

Moon and Antares Two stars with different fates Sunday, March 3, 2013

Moon and Antares A hot-but-cool stellar supergiant Monday, February 4, 2013

Moon and Antares Building a stellar onion Saturday, July 28, 2012

Alpha and Beta Aquarii Rare supergiant stars Tuesday, October 23, 2012

Lucky Stars Lucky stars in the evening sky Monday, October 22, 2012

More Moon and Antares A stellar recycling project Friday, September 21, 2012

Moon, Saturn, and Spica A stellar weight-loss plan Friday, March 9, 2012

Betelgeuse A superstar among supergiants Thursday, December 1, 2011

Rho Cassiopeia Practicing for a big blast Tuesday, October 4, 2011

Deneb Nagging questions about a giant star Tuesday, August 9, 2011

Cygnus The impressive heart of the swan Monday, August 8, 2011

Moon and Antares An unlikely abode for life Wednesday, April 20, 2011

Moon, Venus, and Antares Puffing up a stellar supergiant Friday, January 28, 2011

Alnilam Sailing on a stellar wind Friday, January 14, 2011

Stellar Shock Wave A star rams its way through the galaxy Wednesday, January 5, 2011

Orion's Giants Big stars with spectacular fates Thursday, December 23, 2010

Moon and Antares A matter of scale Monday, September 13, 2010

Rigel A star with a bright but short future Monday, August 16, 2010

Deneb Packing up for a long trip Tuesday, July 27, 2010

Red Rivals Evening up a celestial rivalry Sunday, July 11, 2010

Rasalgethi A long trek for starlight Friday, May 7, 2010

Moon and Antares Feeling the warmth of a giant star Friday, March 5, 2010

Orion The beautiful celestial hunter Monday, February 8, 2010

Moon and Antares Hiding the surface of a star Saturday, February 6, 2010

Magnesium Ready for a dose of magnesium Wednesday, January 20, 2010

Featured Images

Stellar Stunner Monday, December 22, 2014

Future Fireworks Monday, June 16, 2014

Jolly Yellow Giant Thursday, March 13, 2014

Hot Dust Tuesday, January 7, 2014

Dusty Skies Wednesday, December 18, 2013

Stellar Timebomb Thursday, December 1, 2011