The red giant star Betelgeuse: red giants are stars that have exhausted their Hydrogen fuel and are burning Helium and heavier elements.
Click on image for full size
Image courtesy of NASA, Hubble Space Telescope Institute

Creating Elements up to Iron

When the temperature in the core of a star reaches 100 million degrees Kelvin fusion of Helium into Carbon occurs (three Helium nuclei combine to form a nucleus of Carbon). In the same range of temperature Oxygen is also formed from fusion of Carbon and Helium together.

At 500 million degrees Kelvin two Carbon (2 12C) nuclei can fuse to form heavier elements such as Neon (20Ne+4He), Sodium (23Na+1H), and Magnesium (24Mg).

Oxygen can start burning effectively at temperatures on the order of 1 billion degrees Kelvin. The fusion of two nuclei of Oxygen can produce Sulfur (32S), and Silicon (28Si+4He).

The heaviest elements obtainable through a fusion process that releases energy are obtained at a temperature range of 2 billions degrees Kelvin, when two Silicon nuclei can fuse to form Nickel (56Ni). Nickel-56 can then decay into Cobalt and Iron.

Movies courtesy of University of Oregon

Last modified May 10, 2010 by Randy Russell.

You might also be interested in:

Atomic Nucleus

Atoms are composed of a massive, central nucleus surrounded by a swarm of fast-moving electrons. The nucleus is made up of protons and, in most cases, neutrons. Almost all of the mass (more than 99%) of...more

Fusion Inside the Stars

Fusion in the core of the stars is achieved when the density and temperature arising from the gravitational pressure are high enough. There are different fusion cycles that occur in different phases of...more

The Hydrogen Fusion Process

The basic Hydrogen fusion cycle involves four Hydrogen nuclei (protons) and two electrons and yields a Helium nucleus, two neutrinos and six photons. This process occurs in three steps: the first one is...more

The Neutron Capture Process

Neutron capture can occur when a neutron approaches a nucleus close enough for nuclear forces to be effective. The neutron is captured and forms a heavier isotope of the capturing element. When the new...more

The Supernova

A Supernova is a very massive star that explodes at the end of its life cycle. The supernova is the furnace where the heavy elements (heavier than iron) are formed by neutron capture. ...more

IMF

IMF stands for Interplanetary Magnetic Field. It is another name for the Sun's magnetic field. The Sun's magnetic field is enormous and is carried by the solar wind. The solar wind and magnetic field are...more

Fusion Reactions

Nuclear fusion is a process where two or more nuclei combine to form an element with a higher atomic number (more protons in the nucleus). Fusion is the reverse process of nuclear fission. Fusion of light...more

The Cherenkov Effect

The theory of relativity states that no particle can travel at the speed of light in a vacuum. However, light travels at lower speeds in dense media, like water. A particle traveling in water must have...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA