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Stellar Birth. Nikki B Karly B. Interstellar Cloud. An accumulation of dust, gas and plasma that is a denser-than-average region of the interstellar medium. Collapsing Cloud Fragment. The density of the cloud formed begins to decrease.
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Stellar Birth Nikki B Karly B
Interstellar Cloud • An accumulation of dust, gas and plasma that is a denser-than-average region of the interstellar medium
Collapsing Cloud Fragment • The density of the cloud formed begins to decrease. • Photons absorbed by the thin material of the fragment are radiated into space, so no temperature increase occurs. • The fragments continue to contract until they become so dense that radiation can not escape the core of the star.
Fragmentation Ceases • Tens of thousands of years after the second stage, the fragment begins to collapse • The center becomes opaque and the central temperature rises significantly • A protostar appears at the center and the cloud shrinks to the size of our solar system
Protostar • A protostar is the center of the disc formed in the center of the interstellar gas cloud. • Hotter than the gas it condensed, but cooler than a star. • Further collapse occurs when the protostar reaches seven million Kelvin and nuclear reactions begin in the core.
Protostar Evolution • As the protostar moves beyond stage 4, it becomes a T Tauri star, moving toward the main sequence • this path from stage 4 to 6 is known as the Hayashi track • Characterized by violent surface activity and strong protostellar winds • Central temperature is still not hot enough for thermonuclear fusion • repulsion of two positively charged protons (Hydrogen nuclei) cannot be overcome
Newborn Star • After 100,000 years of formation, a newborn star is created. • The temperature of the newborn star begins to increase, causing the fusion of hydrogen to create helium • The remaining dust and gas surrounding the star disperses.
Main Sequence • The star contracts and comes into hydrostatic equilibrium
Works Cited • http://physics.uoregon.edu/~jimbrau/astr122/Notes/Chapter19.html • http://en.wikipedia.org/wiki/Interstellar_cloud • http://physics.fortlewis.edu/Astronomy/astronomy • http://www.nmm.ac.uk/server/show