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

Lepus Bounding past the hunter’s feet Saturday, February 6, 2016
Aludra The showiest “dog” star of all Wednesday, January 13, 2016
The Dog’s Tail The big dog wags its tail — after this. Tuesday, January 12, 2016
Orion Rising A passel of supergiants Monday, November 30, 2015
Runaway Star A stellar “runaway” in the charioteer Saturday, November 14, 2015
Stellar Death Different ways for a star to die Monday, November 2, 2015
Eta Carinae Impressive stellar siblings Tuesday, October 20, 2015
Enif The bright nose of the winged horse Sunday, October 18, 2015
Rare Gems Yellow gems from the water bearer Saturday, October 3, 2015
Moon, Saturn, and Antares A stellar weight-loss plan Saturday, August 22, 2015
Moon and Aldebaran Similar but different lights near the Moon Friday, August 7, 2015
Deceptive Giant A star that’s more impressive than it looks Saturday, June 27, 2015
Moon and Companions A giant star hides in plain sight Tuesday, May 5, 2015
Moon, Saturn, and Antares Gazing at a star among stars Wednesday, April 8, 2015
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

Featured Images

Hubble view of the Eta Carinae system
The Homunculus Wednesday, October 21, 2015
Rigel, the brightest star of Orion
Stellar Stunner Monday, December 22, 2014
Hubble Space Telescope view of Eta Carinae
Future Fireworks Monday, June 16, 2014
A rare yellow hypergiant star in Centaurus
Jolly Yellow Giant Thursday, March 13, 2014
Hot Dust Tuesday, January 7, 2014
RS Puppis, a supergiant star seen by Hubble Space Telescope
Dusty Skies Wednesday, December 18, 2013
Plumes of gas spew into space from the roiling surface of Betelgeuse, the bright
Stellar Timebomb Thursday, December 1, 2011


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