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10 Cards in this Set
- Front
- Back
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Stage 1: Interstellar Cloud |
-begins with a cold dark dust/gas cloud made up of atomic and molecular gas -an eternal event triggers the collapse of the cloud -gravitational instabilities fragment the cloud into 10-1000s of fragments |
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Stage 2: Collapsing Cloud Fragments |
-a sun star requires a fragment cloud containing 1-2 solar masses of H gas and dust -fragments are expected to be 100 times bigger than the diameter of our solar system |
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Stage 3: Fragmentation Ceases |
-fragments shrunk to the size of our solar systems -cloud edges become cold, transparent, and radiate out heat -gases continue to be pulled to the centre -now known as a Protostar |
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Stage 4: Protostar |
-begins to evolve and shrinks, while density and temp increases -brighter than main sequence stars -100x the radius of the sun -once it becomes a hydrogen |
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Stage 5: Protostellar Evolution |
The Hayashi Track: the protostar approaches the main sequence it shrinks to 10x the size of the sun and losses luminosity to 10x that of the sun |
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Stage 6: A New Born Star |
-stars has contracted and internal temp has increased to 10000000k and nuclear fusion starts to occur -surface temp is 4500k |
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Stage 7: Main Sequence Star |
-contracts a little more, central temp: 15000000k -nuclear fusion is in full swing -surface temp 6000k -outward pressures of fusion and inward pressures of gravity are balanced -much like our sun it will stay in this phase for 10 billion years |
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Process Timing |
-takes 40 to 50 million years for the whole process (this is equivalent to 1% of our suns life time) |
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Mass of Cloud and Star Formation |
-the time required for star formation is strongly correlated to the mass of the cloud -the most massive clouds become main sequence O stars (big and blue) in 1 million years |
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Shockwaves and Star Formation |
Sources: 1. star formation 2. death of a star a) ejections of gas shells (red giants) b) supernova 3. density spiral arms 4. gravitational interactions between galaxies |
