Chapter 7

Question 1

Near Earth minor planets populate what region of the SS?

Answer 1

Inner Solar System

Question 2

Main belt minor planets populate what region of the SS?

Answer 2

The middle

Question 3

What is the outer region of the SS populated with?

Answer 3

Comets, plutinos, TNOs, and Scattered Disk objects

Question 4

Where is the asteroid belt located?

Answer 4

Between inner (terrestrial) planets and outer (Jovian) planets

Question 5

What does the asteroid belt contain?

Answer 5

The orbits of all inner SS planetesimals not incorporated into a planet

Question 6

What is the approximate mass of the asteroid belt?

Answer 6

Approx. 5x10^21 kg (1/3 of Pluto)

Question 7

What is the name of the largest asteroid and what is its mass/diameter?

Answer 7

Ceres, Diameter: 940km, Mass: 10^21 kg

Question 8

What is special about Ceres?

Answer 8

It is the only dwarf planet in the asteroid belt

Question 9

Why is there no planet in the asteroid belt region?

Answer 9

Because of Jupiter’s perturbations

Question 10

Can asteroids have their own moons?

Answer 10

Yes

Question 11

What is mean motion resonance in regards to the asteroid belt?

Answer 11

There occurs gaps in the distibution of the asteroid belt at locations where an objects orbit time is a small integer of Jupiter’s (ex. 3:2, 2:1 etc.)

Question 12

What is mean-motion resonance dependent on?

Answer 12

Only the size (average distance form the Sun) of an objects orbit, not its mass.

Question 13

What are the 2 groups of asteroids stabilized by mean-motion resonance from Jupiter?

Answer 13

Hilda (3:2) and Trojan (1:1) groups

Question 14

What are the 4 major asteroid families?

Answer 14

Eos, Hirayama, Themis, Kornois (ojects in grops show similar spectra)

Question 15

What is a Larange Point?

Answer 15

Where Jupiter’s orbit intersects 2 groups of Trojan asteroids (about 120 degrees from each other)

Question 16

How are asteroid families created?

Answer 16

When an asteroid undergoes a collision, it produces fragments which stay near its orbit

Question 17

How do smaller asteroids escape the belt?

Answer 17

Via resonance and solar radiation pressure over long periods of time

Question 18

What are the 4 classes of NEAs and how do their orbits correspond with Earth’s?

Answer 18

Amor (outside), Apollo (fully crosses), Aten (crosses only near aphelion), Atira (inside)

Question 19

What is the minimum orbital distance from Earth’s orbit for a Potentially Hazardous Asteroid?

Answer 19

<0.05AU

Question 20

When larger asteroids prodice fragments, what are the 2 ways they behave?

Answer 20

Either has post-collsional resonance or evolve to a major resonance “escape” hatch

Question 21

What is the name of the effect in which “asymetrical re-radiation of thermal energy for a rotating body can produce a small force that slowly changes its orbit over time”?

Answer 21

The Yarovsky Effect

Question 22

What may occur after the Yarvosky Effect takes place?

Answer 22

The asteroid may be sent into resonance and escape from the asteroid belt

Question 23

What is the relationship between diameter and number of bodies of that diameter in the asteroid belt?

Answer 23

N=1/D^2

Question 24

What is the usual way of determining an asteroid’s size?

Answer 24

Assume a sphere and an albedo of 10%, measure brightness (telescope) and determine distance (orbit), can find geometrical surface area

Question 25

What is albedo?

Answer 25

The fraction of incident light that is reflected

Question 26

What is the density of asteroids compared to meteroites?

Answer 26

The "rubble-pile" (large fragments and small debris) make-up leads to lower density than meteroites

Question 27

How are asteroid classes established?

Answer 27

Based on their spectra

Question 28

What does the spectra of an asteroid indicate?

Answer 28

The minerals present on the surface ONLY

Question 29

How many major classes of asteroids are there?

Answer 29

16 classes

Question 30

What are the 2 main sources of thermal energy in an asteroid?

Answer 30

Collisions (primordial and recent) and radioactivitiy

Question 31

What is the difference between comets and asteroids?

Answer 31

Comets are cold, dusty, volatile/ice-rich; asteroids are rocky, volatile-poor

Question 32

How large is a comet nuclei?

Answer 32

Approx 10-20km in diameter

Question 33

Are comets single bodies or bound rubble piles?

Answer 33

Can be both

Question 34

How close to the Sun must a comet before it begins producing a tail?

Answer 34

Must be approx 3AU for ice to being vaporizing (sublimation temperature of water)

Question 35

How long is a comets tail and which direction does it always point?

Answer 35

Approx 10^8km long and always points away from the Sun

Question 36

What is the name of the cloud of gas around a comet when it is producing a tail and how large is it?

Answer 36

Called a coma, and it is typically 10^4-10^5km across (the further out they form the more volatile the material)

Question 37

Why are comets typically hard to detect?

Answer 37

Their orbits are highly elliptical, which means they are most often inactive

Question 38

What is a "dust crust"?

Answer 38

large non-voalite rock material that builds up as ice disappears

Question 39

Which comets have a dust crust?

Answer 39

Comets that have passed by the Sun many times and have dark (vs. white) surfaces

Question 40

What are long period comets?

Answer 40

Comets with an orbital period longer than 200 years, orbit extends out past planetary nebula (come from Oort Cloud)

Question 41

What are short period comets?

Answer 41

Comets with orbits less than 200 years, inclinations similar to planets', come from Kuiper-belt (just outside Neptune's orbit)

Question 42

How are comets removed from the Oort Cloud?

Answer 42

Can be slingshot by the perturbations of passing stars

Question 43

How large is the Oort cloud and what determines the edge?

Answer 43

The edge is approx 50,000 AU from Sun, defined by the edge of "stable" orbits

Question 44

How many 1km diamter or greater objects are located in the Oort Cloud?

Answer 44

Approx 10^12

Question 45

How are half of the SS comets ejected?

Answer 45

Their orbits are disturbed by planets while in perihelion

Question 46

How many comets make up the Kuiper Belt?

Answer 46

Approx 10^9-10^10

Question 47

Why dont these comets typically develop tail?

Answer 47

Their orbits have low eccentricity, therefore are never brought too close to Sun (can be picked up by Neptune and sent into inner SS though)

Question 48

What are KBO with 3:2 resonance with Neptune? 2:1?

Answer 48

Plutinos (3:2), and Twotinos (2:1)

Question 49

What is the gas to dust ratio in a comet?

Answer 49

About 1 to 100

Question 50

What is a Dust Tail

Answer 50

A tail formed, separate from an gas tail, that is yellowish in colour