Evolution of the Solar System

1. Evolution of the Solar System Matt Rogers AT350 9 September 2003

2. Overview • Evolution of a star • Interstellar Nebula • Formation of protostar and protostellar nebula • Evolution of early sequences and dissipation of protostellar nebula

3. Overview (continued) • Evolution of planets • Protostellar nebula makeup • Evolution of protostellar nebula • Formation of planetisimals • Terrestrial Planets • Jovian Planets • Endgame

4. Interplanetary Nebula

5. Protostars and Protostellar Nebulae Accretion of nebular gases form protostar Protostar starts sucking in nearby nebular gases, forms local increase in nebular gas amount – we call this a protostellar nebula

6. A Star Is Born • Protostar continues accreting mass, becomes more and more massive • Fusion process in star core initiates • Increase in solar wind blows protostellar nebula away (but not planets) • Star enters main sequence

7. Protostellar Nebulae and You:How Planets Are Formed • Mostly H and He, with other interesting elements (but nothing heavier than Iron) • Depending on protostellar nebula temperatures, can combine to form other molecules – carbon dioxide, water, hydrocarbons, even rocks!

8. Protostellar Nebulae and You:How Planets Are Formed • Near hot protostar, only rocks accrete – too hot for hydrocarbon/water ices • Outside of the frost line, both rocks and solid ices form • Composition of planetesimals depends on where you are in regards to the frost line

9. Formation of terrestrial planetesimals • Chunks of rock orbiting the protostar slam into each other, form rudimentary planets, called planetesimals • Planetesimals contain rocks and heavy gases such as water vapor, CO2, nitrogen, etc., with a rudimentary H and He atmosphere

10. Formation of Jovian planetesimals • Planetesimals similar to terrestrial variety, except that they grow faster, since they’re accreting rocks and solid ices • Become massive more rapidly, eventually become large enough to capture H and He from the surrounding nebula (if it’s dense enough) – this is how gas giants are formed • If there’s not enough nebular gas (i.e. a long way from the sun) the small planetesimals remain as comets

11. Final Stages • Nebular gas ejected from solar system, planets remain and begin to cool

12. The Early Earth • Earth cools (having lost early H and He atmosphere), begins outgassing water, cabon dioxide and nitrogen gas • Early oxygen released from silicate materials, bulk from photosynthesis later • From here on out, just like in the notes!

13. Fin.