Formation of the Solar System Flashcards
What was the composition of the disk surrounding the Sun?
98.5% gas
1.5% dust
How long did it take for the solar accretion onto sun to finish?
Solar nebula contracted and flattened and formed protostar in 100,000 years.
What is Age Zero of the solar system?
Where nuclear fusion takes over contribution to luminosity
What happens to planetestimals in early stages?
Collide and grown forming a few large planets
What are the two factors that affect where planets form in the solar system?
Turbulence in disk
Temperature of disk
How does turbulence affect planet formation?
Too turbulent: particles move too fast and bounce off each other
Less turbulent: greater chance that particles collide and stick
How does disk temperature change moving out?
Temperature falls of 1/distance squared moving away from star
What is the critical point for disk temperature?
The ice line where beyond this hydrogen compounds condense into solid ice grains.
What is Disk like between 0.8 and 1.3AU?
Dust very hot - 1000K and wont contain any water
What is the Disk between 2 and 5 AU?
Lower temp - 500K
Volatile organics stay solid
What is the disk like Beyond 5 AU?
Low temp - 150K
Water is as water-ice that is key for planet cores
What would happen without any turbluence at all?
Objects of a few km would form from gravity
How long for process to take to produce objects bigger than 1km?
1000-100,000 years
After 100,000 years how many objects of 1-10km size expected?
100 billion surrounded by nebular gas and gradually collide
Nature of inner planetesimals
Rocky with sufficient local gravity to retain passing dust but not capture gas
Nature of outer planetesimals
Large amounts of water-ice
Higher masses so can capture and retain gases
After 1 million years of agglomeration?
Inner zone contains 20 objects size of our moon.
Outer zone only a few large objects
What do Massive objects in late agglomeration do?
Attract smaller objects and speed up accumulation
What happens to Smaller objects in late agglomeration?
More fragmentation if they collide and slowed due to larger objects
Two types of planets
Gas Giants
Terrestrial or rocky
Gas Giant Properties
Mass greater than 10 Earths necessary.
Only beyond ice line
Hold large amounts of H gas
Rocky planets properties
Rock and metal.
High density
Slow rotations
Solid surface
No rings
What is found in front of the freezing point and behind it?
Metals in front
Silicates/rocky material behind
