Formation of the Solar System

Question 1

What was the composition of the disk surrounding the Sun?

Answer 1

98.5% gas
1.5% dust

Question 2

How long did it take for the solar accretion onto sun to finish?

Answer 2

Solar nebula contracted and flattened and formed protostar in 100,000 years.

Question 3

What is Age Zero of the solar system?

Answer 3

Where nuclear fusion takes over contribution to luminosity

Question 4

What happens to planetestimals in early stages?

Answer 4

Collide and grown forming a few large planets

Question 5

What are the two factors that affect where planets form in the solar system?

Answer 5

Turbulence in disk
Temperature of disk

Question 6

How does turbulence affect planet formation?

Answer 6

Too turbulent: particles move too fast and bounce off each other
Less turbulent: greater chance that particles collide and stick

Question 7

How does disk temperature change moving out?

Answer 7

Temperature falls of 1/distance squared moving away from star

Question 8

What is the critical point for disk temperature?

Answer 8

The ice line where beyond this hydrogen compounds condense into solid ice grains.

Question 9

What is Disk like between 0.8 and 1.3AU?

Answer 9

Dust very hot - 1000K and wont contain any water

Question 10

What is the Disk between 2 and 5 AU?

Answer 10

Lower temp - 500K
Volatile organics stay solid

Question 11

What is the disk like Beyond 5 AU?

Answer 11

Low temp - 150K
Water is as water-ice that is key for planet cores

Question 12

What would happen without any turbluence at all?

Answer 12

Objects of a few km would form from gravity

Question 13

How long for process to take to produce objects bigger than 1km?

Answer 13

1000-100,000 years

Question 14

After 100,000 years how many objects of 1-10km size expected?

Answer 14

100 billion surrounded by nebular gas and gradually collide

Question 15

Nature of inner planetesimals

Answer 15

Rocky with sufficient local gravity to retain passing dust but not capture gas

Question 16

Nature of outer planetesimals

Answer 16

Large amounts of water-ice
Higher masses so can capture and retain gases

Question 17

After 1 million years of agglomeration?

Answer 17

Inner zone contains 20 objects size of our moon.
Outer zone only a few large objects

Question 18

What do Massive objects in late agglomeration do?

Answer 18

Attract smaller objects and speed up accumulation

Question 19

What happens to Smaller objects in late agglomeration?

Answer 19

More fragmentation if they collide and slowed due to larger objects

Question 20

Two types of planets

Answer 20

Gas Giants
Terrestrial or rocky

Question 21

Gas Giant Properties

Answer 21

Mass greater than 10 Earths necessary.
Only beyond ice line
Hold large amounts of H gas

Question 22

Rocky planets properties

Answer 22

Rock and metal.
High density
Slow rotations
Solid surface
No rings

Question 23

What is found in front of the freezing point and behind it?

Answer 23

Metals in front
Silicates/rocky material behind