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Flashcards in Lecture 8 Deck (34):
1

What is strange about the "disappearing star" KIC 8462852?

There are irregular dips in the light output, suggesting something large is coming in front of the star periodicially

2

What is a Dyson sphere?

A suggested answer to the problem of the star dimming; a huge metal structure built to capture light

3

What properties of the solar system must the formation theory explain?

1. Formation of sun 2. Patterns of motion 3. exceptions 4. Existence of three types of planets 5. existence of smaller bodies

4

What were the two prevailing theories?

Nebular and close encounter

5

What was the nebular theory?

Theory that solar system formed when a cloud of dust collapsed

6

What was the close encounter hypothesis and why was it disproved?

It stated that a nearby star came in and caused large chunks of debris to form the planets; but can't be true because that is highly improbable and wouldn't account for the different patterns of motion

7

What is one example where we can see stars forming?

The Orion Nebula

8

How does contraction produce heat?

Friction and radiation of collapsing

9

Why should a cloud start collapsing?

After a cataclysmic event

10

What three things happen to a spinning cloud?

Heating, Spinning, Flattening

11

Why do collapsing clouds heat up?

Due to the gravitational energy

12

Why do collapsing clouds spin faster?

Due to the change in angular momentum

13

Why do collapsing clouds flatten?

Because as particles collide they form clumps, and this helps to organize the motion

14

What three things constrain the possibility of a collapse?

Low density, too hot, too large

15

What happens in star formation once the large cloud collapses?

Smaller clouds form due to various things, for example magnetic fields

16

What is interesting about view T Tauri star?

It is embedded in a nebula

17

What was the era of Heavy Bombardment?

The time when most craters formed

18

What are Herbig Haro objects?

Stellar jets of gas

19

Why did different types of planets form?

Due to the different temperatures at which compounds condense

20

What is the frost line?

The line which marks where hydrogen compounds may start to condense

21

How did the terrestrial planets form?

Accretion

22

How did captured moons occur?

By random objects getting trapped in gravitational field

23

How can we tell if a moon is a captured moon?

Usually quite small, retrograde orbit, or tiled at a funky axis, funky shape

24

What are the four steps to planetary formation?

1. Dust sticks together
2. Orderly growth
3. Runaway growth
4. Oligarchic growth (of only certain planets)

25

Why do we suspect Itokawa is a planetesimal?

It has two distinct chunks that seemed to have formed together

26

How did the jovian planets form?

Ice condensed as well as other materials, and they got so big because they had a much larger area to sweep, and eventually could get even H and He to become part of their atmosphere

27

Why does migration occur after planets have formed?

Due to friction from the dust

28

What is type 1 migration?

Body slows down due to friction of being embedded in dust, slowly moves inward

29

What is type 2 migration?

Body gathers up more dust, affecting the mass and therefore angular momentum of the body

30

What is High Eccentricity Migration (HEM)?

Gravitational interaction with another body, kicking one out or in

31

What happens after all formation is done?

Solar wind blows dust and gas away, other factors contribute to blowing the disk away

32

When do comets and asteroids form?

After accretion, icy comets outside frost line, rocky asteroids inside frost line

33

Where did Earth's water come from?

Chondrites -- certain chemicals delivered during Heavy Bombardement

34

Why does Uranus have such a crazy tilt?

It got hit multiple times during Heavy Bombardment