recycling_2-1 - Most star formation occurs in the disk, and...

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Our galaxy: the milky way Total mass: 1 trillion Msun ~100 billion Msun is stars ~few 100 billion Msun is ags ~500 billion Msun is dark matter Molecular clouds are really the dark Nebula May also be pre-star forming clouds Give galaxy its splotchy appearance Light absorption is due to dust The formation of massive stars produce ionization nebula Has strong emission lines Since massive stars have a short lifetime, their presence indicates a star forming region Halo: no ionization nebula, no blue stars Disk: ionization nebula, bule star
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Unformatted text preview: Most star formation occurs in the disk, and more specifically in the spiral arms Explained observed star formation 1. gas clouds get squeezed as they move into spiral arms 2. squeezing of clouds triggers star formation 3. young stars flow out of spiral arms Young blue stars are formed Ionization nebula arise where newly forming blue stars are ionized has clouds Halo stars: 0.02-0.2% heavy element, only low mass stars Disk stars: 2% heavy elements, stars of all masses...
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