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 YouHow 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 YouHow 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 theyre
  accreting rocks and solid ices
• Become massive more rapidly, eventually become
  large enough to capture H and He from the
  surrounding nebula (if its dense enough) this
  is how gas giants are formed
• If theres 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.