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ExploraTour: A Peek into the Lives of the Stars

What Happens to High Mass Stars (>8 Solar Masses)?

STAGE 2: Red Supergiant Phase

After the star depletes the hydrogen in its core and moves off the main sequence, the core contracts and heats causing the outer layers to expand. The expansion of the outer layers results in a cooling of the surface temperature. The star gets redder but stays about the same brightness. This happens because it is increasing rapidly in size. It first becomes a blue supergiant (like Rigel) and then cools and expands to a white supergiant (like Deneb).

Meanwhile the core is getting hotter reaching 150 million K. At this temperature, helium (He) fuses explosively into carbon (C) and oxygen (O). For lower mass stars, nuclear reactions at this stage cease and the star collapses to a white dwarf. But red supergiants are much more massive.

Gravitational collapse continues to raise the temperature of the core. When the core reaches an amazing 1 billion K, carbon fuses to produce nitrogen (N), magnesium (Mg) and oxgyen (O). These elements fuse to produce even heavier elements.

At each stage less total energy is released and thus the stages get progressively more short-lived. Finally an iron core is produced. Since no energy can be gained by fusing iron to make higher mass elements, the core collapses at blinding speeds.

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Traveling Nitrogen Classroom Activity Kit

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

Element (Chemical Element)

An element (also called a "chemical element") is a substance made up entirely of atoms having the same atomic number; that is, all of the atoms have the same number of protons. Hydrogen, helium, oxygen,...more

ExploraTour - Looking at the World in a Different Light

Even though the sleeping man is no longer on the bed, you can still see where he was lying down. The heat from his body warmed up the bed sheets which are now radiating infrared light toward your eyes....more

ExploraTour - Looking at the World in a Different Light

All warm objects radiate in the infrared. The warmer the object, the higher the frequency and intensity of the radiation. Very hot objects give off other types of radiation in addition to infrared. Click...more

ExploraTour - Looking at the World in a Different Light

Your eye is a wonderful detector of visible light. Different frequencies of light produce different sensations in the eye which we interpret as colors. Our eyes detect light by using light sensitive components...more

ExploraTour - Looking at the World in a Different Light

Imagine you found a pair of special glasses that not only gave you telescopic vision but gave you the ability to see all forms of radiant energy. The universe in visible light contains all the familiar...more

ExploraTour - Looking at the World in a Different Light

This is a volcano on the island of Miyake in Japan. It has erupted, sending hot lava and ash into the air, a total of ten times. The time after one eruption until the next occurred was about twenty years...more

ExploraTour - Looking at the World in a Different Light

The awesome power of a giant black hole was revealed by looking at this galaxy in three different types of light. The picture that you see is of Centaurus A, a very peculiar galaxy. A galaxy is just a...more

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