Astronomy Terms For 2Nd Half

Front 1

What are Main Sequence Stars?

Back 1

Any star fusing H to He in its core

Front 2

What is the composition of a star?

Back 2

Our sun is 99.8% H & He; and 0.2% "metals"

Front 3

What are the conditions for fusion?

Back 3

Extremely high temperature and extremely high pressure

Front 4

What allows for extremely high temperature?

Back 4

protons move fast enough to overcome repulsion & collide

Front 5

What allows for extremely high pressure?

Back 5

Protons are VERY crowded together which increase the chance of many, many collisions which maintains a lot of energy

Front 6

What does the mass of a main sequence star effect? Name 6

Back 6

1. Stellar Radius
2. Core Temp., core pressure
3. Star's luminosity
4. Surface Temp.
5. Stellar lifetime
6. End state of a star

Front 7

What defines the size of a low mass star?

Back 7

less than 8 solar masses

Front 8

Wha is the evolution of a low mass star? 4 steps

Back 8

1. Stable fusion of H to He
2. Fuel runs out in its core
3. Outer Atm. expands and cools -> red giant
4. outer layers escape
-> hot,dead solar core
-> white dwarf

Front 9

What is the evolution of a high mass star? 5 Steps

Back 9

1. MS phase
2. Red Giant
3. Huge temperature in core
-> He fusion -> carbon
Carbon + He -> oxygen
Oxygen + He -> Mg
4. Multiple layers of fusion with many elements & core of iron
5. Core collapses, entire star collapses -> supernova! (star then explodes)

Front 10

What is the importance of a supernova?

Back 10

1. Creation of lots of metals
2. Dispersal of metals throughout the region
3. Metals -> planets, moons, asteroids, comets
4. Metals -> Life!
5. Shockwave from a supernova -> creates new stars & solar systems

Front 11

What is the metals vs. time?

Back 11

-Big Bang -> only H/He lots of energy
-Originally no planets/no life possible
-Every SN generation -> more metals
-metal content of universe increases over time

Front 12

What is the age constraint of very old stars?

Back 12

formed when galaxy was very metal poor -> no planets & few organics

Front 13

What is the age constraint of very young stars?

Back 13

not enough time to form planets/life/intelligence

Front 14

What is the mass constraints for too massive stars?

Back 14

-very short lifetime
-too luminous (HZ must be further)
-Lots of UV

Front 15

What is the mass constraints for too low mass stars?

Back 15

-Very low TOTAL energy emitted -> HZ must be VERY close
-Peak radiation is in IR -> weak energy

Front 16

What are the 3 types of solar systems?

Back 16

1. single star
2. binary stars
3. star cluster

Front 17

What are the characteristics of a single star solar system?

Back 17

one energy source & one source of gravity

Front 18

What are the characteristics of a binary star solar system?

Back 18

-2 energy sources (too much energy for temp. stability)
-2 sources of gravity (danger of unstable orbit, ability to even form the planet)

Front 19

What are the characteristics of a star cluster solar system?

Back 19

-many energy sources
-many gravity sources
-can planets even form?

Front 20

What are the 4 constraints of location in the galaxy?

Back 20

galactic center, Halo, edge of galactic disc, and glactic disk/spiral arms

Front 21

What are the characteristics of the galactic center?

Back 21

-stellar density is way too high
-too many enemy/gravity sources
-huge amounts of x Rays and gamma rays

Front 22

What are the characteristics of the halo?

Back 22

-globular clusters
-too many energy/gravity sources
-very old stars-> poor metal content

Front 23

What are the characteristics of the edge of galactic disc?

Back 23

very metal poor

Front 24

What are the characteristics of the galactic disk/spiral arms?

Back 24

- lots of single stars
- lots of young stars
->good metal content

Front 25

Sum up the 4 Key Stellar constraints

Back 25

Age, Mass, Types of solar systems, and location in galaxy

Front 26

What is the importance of atmosphere?

Back 26

-Protection from UV/X rays/ Gamma rays
-Greenhouse effect (holds in heat)
-> creates small day/night temp. differences

Front 27

What are the negative effects of a low mass terrestrial?

Back 27

-low gravity->weak to hold atm.
-cool interior- no molten core & no magnetosphere & no geology

Front 28

What are the negative effects of a high mass terrestrial?

Back 28

-Stronger gravity ->atm. becomes too thick
-Strong gravity -> higher chance of collision by comet/asteroid
-Interior is "too hot"
-> too much geology - too much source of CO2 -> atm. too thick
-Strong gravity -> planet can retain Hydrogen which leads to potential production of NH3 & CH4 ->these chemicals may be posionous to life

Front 29

What is the range of mass for a habitable terrestrial?

Back 29

.93 Earth Masses < MC 1.33 Earth Masses

Front 30

How does the HZ relate to the habitbaility of a terrestrial?

Back 30

the HZ is a region in the vicinity of a star where temp. are such that H2O, if it exists, will be in liquid form

Front 31

How does the HZ relate to a more luminous star?

Back 31

HZ is further away

Front 32

How does the HZ relate to a less luminous star?

Back 32

HZ is closer

Front 33

How does slow rotation speed effect a planets habitability?

Back 33

Weak magnetic field & large day/night temp. differences

Front 34

What are the consequences of a very close HZ?

Back 34

-if star/planet are very close & with large gravity/tides, planets rotation is slowed to "synchronous rotation"
-day side is always day -> too hot
night side always night -> too cold

Front 35

What is the effect of a large Jovian (jupiter)?

Back 35

-sweeps up lots planetary debris -> fewer impacts on Earth

Front 36

What is the effect of our moon?

Back 36

-some objects hit moon, not us
-moons gravity stabilizes Earth's tilt at 23.5 degrees
-> maintains seasons as pretty constant

Front 37

Sum up the 6 major Terrestrial Habitability charcteristics

Back 37

Atmosphere, mass, HZ, Rotation speed, large jovian,
moon

Front 38

What are the 3 categories for planet forming materials?

Back 38

1. Gases
2. Ices/Volatiles
3. Rocks/Metals

Front 39

What are the characteristics for gases?

Back 39

Like H/He they are very abundant and are never solid

Front 40

What are the characteristics for ices/volatiles?

Back 40

Like H20/CO2/NH3/CH4 they are somewhat abundant and are only solic at low temps

Front 41

What are the characteristics for Rocks/Metals?

Back 41

Like iron/Si/Al they are not abundant and are always solid unless the temp. is VERY high

Front 42

What are the characteristics of the Extreme inner solar system?

Back 42

1. few tenths of an AU from the Sun
2. Temp is > 2000K
3. H/He; Ices/Volatiles; & Rocks/Minerals are all gaseous
4. Planets cannot form here

Front 43

What are the characteristics of the inner solar system?

Back 43

1. .35-3 AU
2. temps range from hot->medium->warm
3. gases and ices are still gaseous but rocks/minerals can be solid and can form planets
4. Low abundance: small planets
5. High denstiy b/c they are made of heavy material

Front 44

What are the characteristics of the Outer solar system?

Back 44

1. 4 AU & beyond
2. very cold
3. Gases are still gaseuous but ices & rocks/minerals are solid
4. Jovian core is made from R/M & lots of ices -> huge cores
5. Huge plantary cores gather huge atm. of h/he -> enormous mass and low density b/c of h/he composition.
6. ices -> moons & comets

Front 45

What is the idea of late heavy bombardment?

Back 45

3.9 million ys. ago the ISS planets were bombarded by many comets from OSS and these impacts deposited H2O & organic chamicals

Front 46

What are the consequences of a large Jovian?

Back 46

1. sucks up planetary debris
2. circular orbit: no gravitional influences which could eject another planet into the sun or deep into space
3.Jupiter may have robber Mars of significatn mass during formation
4. Jupiter may have robbed losts os mass from "5th planet" -> asteroid belt!
5. Large jovian -> huge tidal forces ->warm interior of Io/Europa

Front 47

Sum up the 6 planetary functions

Back 47

1. Planet forming materials
2. EISS
3. ISS
4. Outer SS
5.Late Heavy Bombardment
6. Consequences of a large Jovian

Front 48

What are the detection methods of Extra solar planets?

Back 48

1. Direct Detection
2. Stellar wobble
3. Doppler Shift
4. Planetary occultation (eclipse)

Front 49

What is direct detection?

Back 49

to "see" a planet

Front 50

How does one "see a planet?"

Back 50

Planets shine by reflected sunlight (visible light) and in this light starts outshing planets by a factor of 250M -> 1 billion times

Front 51

How does one view an IR star?

Back 51

these stars outshine by 1000-10000x and IR does not penetrate our atm. easily and makes it almost impossible to resolve

Front 52

What is stellar wobble?

Back 52

planet & star orbit around a common cneter-of-mass (barycenter) and the planet causes the star to orbit the barycenter which allows us to see the "wobbling effect"

Front 53

What is the difference in wobbles from small to large planets?

Back 53

small planets create a very ting wobble and large planets create a larger wobble. This process is best for finding jovians

Front 54

What is the doppler shift?

Back 54

-Spectral lines indicate motion towards->away->towards->away
-Repeating blue shift <-> red shift behavior -> there is a planet

Front 55

What is the data derived from the doppler shift?

Back 55

planet mass, oribtal distance, revolution period, orbital shape and orbital inclination

Front 56

What is planetary occultation?

Back 56

This occurs only if orbital plance is seen edge-on and everyrime a planet transits we see a small dip in its star's brightness

Front 57

What are the results of the detection methods?

Back 57

-150+ extra-solar planets found

Front 58

What are the results of the detection methods in terms of planet masses?

Back 58

most are bigger than jupiter and no terrestrials

Front 59

What are the results of the detection methods in terms of planet orbits?

Back 59

many jovians with eccentric orbits, orbits within 1 AU of star -> hot jovians
-only 18 jovians found beyond 3 AU

Front 60

How many multi planet systems have been found?

Back 60

18

Front 61

What are the 4 major questions about extrasolar planets?

Back 61

1. Why are there jovians in ISS or EISS?
2. Why are orbits soo eccentric?
3. Why are there so few multi-planet systems?
4. Could Jovians moons be habitable?

Front 62

What is the implication to Why are there jovians in ISS or EISS?

Back 62

1. Jovians probably did form in OSS and migrated and spiraled towards the star after accreting gas/dust.
2. Could this process graveject terrestrial planets?

Front 63

What is the implication to Why are orbits soo eccentric?

Back 63

- This could also graveject terrestrials from their orbits

Front 64

What is the implication to Why are there so few multi-planet systems?

Back 64

Too small to find or they are gone?

Front 65

What is the implication to Could Jovians moons be habitable?

Back 65

Potentially Yes

Front 66

Film Questions

Back 66

The Hunt for Alien Worlds Questions

Front 67

What is the best technique for detecting planets?

Back 67

detecting wobbling stars

Front 68

What is the SETI system?

Back 68

Used to detect radio waves throughout the universe and to listen for oncoming messages

Front 69

What mission was used ti prove our capabilities of looking at other planets throughout the universe?

Back 69

The galileo mission

Front 70

What is the principle of Mediocrity?

Back 70

1. our sun is 1 of billions of similar stars: not unique
2. Milky way is 1 of millions of galaxies: not unique
3. PLanets form around other stars
4. Spectroscopy proves that chemicals found here are found everywhere
5. Laws of physics/chemistry are universal
6. If life exists here, why not elsewhere?