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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

Sigma Scorpii Impressive stars near the scorpion’s heart July 30, 2017

Double Bright The leading lights of Pegasus July 29, 2017

Alpha Lupi A bright star with a brighter future July 7, 2017

First Blast A powerful blast from the past July 2, 2017

More Lepus Revving up a massive star January 29, 2017

Bellatrix A truly “bewitching” star November 26, 2016

VV Cephei A “kingly” star in the northern sky October 26, 2016

Runaway Giant A giant star that’s running away from home October 19, 2016

Sadr A supergiant with a rare tint August 9, 2016

Deneb Circling around a giant star August 2, 2016

Heaviest Star A star with a weight problem July 6, 2016

Tarantula Nebula Making stars by the basketful July 5, 2016

Puppis Breaking up a mighty ship March 26, 2016

Lepus Bounding past the hunter’s feet February 6, 2016

Aludra The showiest “dog” star of all January 13, 2016

The Dog’s Tail The big dog wags its tail — after this. January 12, 2016

Eta Carinae Impressive stellar siblings October 19, 2015

Enif The bright nose of the winged horse October 17, 2015

Rare Gems Yellow gems from the water bearer October 2, 2015

Moon, Saturn, and Antares A stellar weight-loss plan August 21, 2015

Moon and Aldebaran Similar but different lights near the Moon August 6, 2015

Deceptive Giant A star that’s more impressive than it looks June 26, 2015

Moon and Companions A giant star hides in plain sight May 4, 2015

Moon, Saturn, and Antares Gazing at a star among stars April 7, 2015

Bright Paw The big dog’s brilliant paw February 12, 2015

Rigel The hunter’s complicated foot December 21, 2014

Even Brighter A couple of brilliant ways to die November 4, 2014

Brighter A bright star gets even brighter November 3, 2014

Sadr A case of stellar WYSIWYG October 13, 2014

Moon, Mars, and Antares Heating up the daytime sky September 28, 2014

Biggest of the Big The monsters of the Milky Way September 22, 2014

Sigma Scorpii Impressive stars near the scorpion’s heart August 8, 2014

Moon and Antares Inflating a stellar supergiant August 4, 2014

Eta Carinae Building up to a big eruption June 15, 2014

Moon and Antares The amazing fate of a giant star June 10, 2014

Alnilam A bright buckle for the hunter’s belt February 15, 2014

Wezen Dumping chemicals into space January 28, 2014

Mirzam Revving up a celestial dog January 27, 2014

M101 ULX-1 Weirdness in a nearby galaxy January 15, 2014

More Aquarius A pair of yellow supergiants December 7, 2013

Orion Rising Jumbo stars climb into view November 21, 2013

Megastars “Megastars” in a nearby galaxy July 8, 2013

Moon and Antares Evidence of ancient chemical factories March 29, 2013

Moon and Antares Two stars with different fates March 2, 2013

Moon and Antares A hot-but-cool stellar supergiant February 3, 2013

Moon and Antares Building a stellar onion January 6, 2013

Alpha and Beta Aquarii Rare supergiant stars October 22, 2012

Lucky Stars Lucky stars in the evening sky October 21, 2012

More Moon and Antares A stellar recycling project September 20, 2012

Moon, Saturn, and Spica A stellar weight-loss plan March 8, 2012

Featured Images

Infrared image of Alpha Camelopardalis

Plowing Through the Galaxy January 25, 2017
Sun vs. VV Cephei

Home of the Whopper October 26, 2016
R136, a massive star cluster in the Large Magellanic Cloud

Biggest of the Big July 6, 2016
Hubble view of Bubble Nebula

Bubbly Star April 21, 2016
Hubble view of the Eta Carinae system

The Homunculus October 21, 2015
Rigel, the brightest star of Orion

Stellar Stunner December 22, 2014
Hubble Space Telescope view of Eta Carinae

Future Fireworks June 16, 2014
A rare yellow hypergiant star in Centaurus

Jolly Yellow Giant March 13, 2014

Hot Dust January 7, 2014
RS Puppis, a supergiant star seen by Hubble Space Telescope

Dusty Skies December 18, 2013
Plumes of gas spew into space from the roiling surface of Betelgeuse, the bright

Stellar Timebomb December 1, 2011