Star Death, Page 47: [Previous Page] [Next Page] [Class Home Page] Textbook pages 345 - 365

The Death of High Mass Stars

A massive star's core burns furiously fast. As it fuses larger atoms together, it does so faster and faster, trying to maintain adequate pressure on the inside to offset the gravitational pressure pushing in from the outside. Below is the time scale over which a star 25 times the mass of the sun, burns its internal fuel:

Burning Stage	Surface T (K)	Radius	Seconds (Yrs)
Hydrogen	40,000	6 Rsun	2.3 x 1014 (7 Mill)
Helium	16,000	70 Rsun	2.1 x 1013 (500,000)
Carbon	4,300	100 Rsun	5.2 x 109 (100)
Neon	4,300	100 Rsun	3.9 x 107 (1 yr)
Oxygen	4,300	100 Rsun	1.6 x 107 (6 mos)
Silicon	4,300	100 Rsun	1.2 x 105 (1 day)
Iron	4,300	100 Rsun	0.35 seconds

note: 3 x 10⁷ second = 1 year

When the core becomes solid Fe, there is no further energy production and the core immediately collapses within just a few seconds! The core collapse raises the temperature to several billion degrees. The Fe nuclei collide so violently they crush into neutrons. This releases an astronomical amount of energy from the core, which we see as a ..

Supernova!

Supernovae are perhaps the most spectacular astronomical events to occur since the original Big Bang! During a supernova, a single star will have the light output of an entire galaxy full of Billions of stars! In February, 1987, a supernova went off in the Large Magellanic Cloud, called: Supernova 1987A. This was a tremendous opportunity for Astronomers (the last naked eye Supernova was in 1604).