Investigating Astronomy Timothy F. Slater, Roger Freeman

Investigating Astronomy Timothy F. Slater, Roger A. Freeman

Chapter 11Inferring Patterns inStar Life Cycles

Star Formation

Observations across the sky reveal that stars form within cold, dark clouds of gas and dust that are scattered abundantly throughout our galaxy.Like the mythical phoenix, all new stars arise from the ashes of the old.

Interstellar Gas and DustThe space between the stars is NOT vacant, but filled with a thin gas laced with microscopic dust particles: the interstellar medium.Clouds of interstellar medium are known as nebula (plural nebulae).

Emission NebulaeAn emission nebula emits its own light, with the characteristic emission spectra similar to that of a hot, thin gas. Emission nebulae are found near hot, luminous stars of spectral types O and B.

Dark NebulaeA dark nebula is so opaque that it blocks any visible light coming from stars that lie behind it.Some astronomers call this nebula The Cosmic Gecko