Stars

Life cycles and Nuclear FusionTaylor Wilson

How are they born?

• Stars born within nebulae – Orion Nebula

• Knots arise as dust particles collect– Collapse

• When nuclear fusion begins, a star is “born”

Nuclear Fusion

• Core is environment of extreme pressure and temperature– 15 million K

• Counteracts forces of gravitational attraction

• Fuses together lighter elements to create heavier ones at core

• Exothermic process• Energy released in the form of

gamma rays

More on Fusion

Remember Newton’s 3rd Law?...

Deuterium and Tritium are both isotopes of hydrogen. Deuterium is stable while Tritium is slightly radioactive.

Maday! We’re out of hydrogen…

• Star leaves main sequence • The most massive of stars can fuse other

elements (helium-iron) when deprived of hydrogen

• Red giant • Next size determines the star’s fate

The Cycle Continues

• The mass lost by the star (supernova or shedding outermost layers), in turn gathers elsewhere in the universe to create new stars!

Bibliography

• Cain, Fraser. "Nuclear Fusion in Stars." Universe Today RSS. N.p., 12 Feb. 2009. Web. 07 July 2014.

• Choi, Charles Q. "Stars: Formation, Classification and Constellations." Space.com. Purch, 15 Nov. 2010. Web. 05 July 2014.

• "Stars - NASA Science." Stars - NASA Science. NASA, n.d. Web. 07 July 2014.