Evolution of the Solar System Matt Rogers AT350 9 September 2003

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

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

Interplanetary Nebula

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

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

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!

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

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

Formation of Jovian planetesimals Planetesimals similar to terrestrial variety, except that they grow faster, since they’re accreting rocks and solid ices 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 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 If there’s not enough nebular gas (i.e. a long way from the sun) the small planetesimals remain as comets

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

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!

Fin.