Fallon, Ryan, Karthik, Catherine

A Star is Born (Option 9)

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The Nebula

Stars begin as molecular clouds, or dense concentrations of interstellar dust and gas. These cold regions of hydrogen and helium are in a balance of their inward force of gravity and outward pressure of the molecules in the cloud.

The Protostar

Protostars are formed when the nebula, or cloud of dust and gas, collapses upon itself due to an imbalance of gravity. This collapsed mass becomes increasingly bright, dense, and hot. Protostars are characterized by unimaginably high temperatures and pressures and the emission of red long-wave light.

The Main Sequence

Main sequence stars generate their own light and heat through nuclear reactions. During a star's main sequence, hydrogen fuses to form helium. The luminosity of a main sequence star depends on its mass. Stars spend the majority of their lives in this stage. Stars vary in color ranging from red to blue, red being the coolest, and blue being the hottest.

Layers of Our Star, the Sun (Option 8)

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Surface Temperatures of Stars (Option 1)

The color of a star is established from its surface temperature and mass. The hottest stars we see appear to be a bright blue and are greatest in mass, cooler stars are yellow with a medium amount of mass, while red stars are the coolest and have the least amount of mass.
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Red Stars

A star that emits mostly red light will have a surface temperature of about 3,500 Kelvin. Red stars are the most common stars in our universe and these stars fuse atoms of hydrogen into helium creating immense amounts of heat.

Yellow Stars

The yellow star is one of the stars that you may know the most about. Our Sun is a yellow dwarf star and is currently in its main sequence fusing hydrogen to form helium, and will continue to do so for another 7 billion years. A yellow star has a surface temperature of about 5-6000K.

Blue Stars

The hottest stars we know of are Blue. Their temperatures start at around 10,000 Kelvin, and the biggest, hottest, most massive supergiants can peak to about 40,000K. These stars also fuse hydrogen into helium, along with other traces of elements.