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1
Q

what planet properties can be found - radial velocity

A

min mass, period, semi-major axis, eccentricity

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2
Q

what planet properties can be found - transit

A

radius of planet, period, semi-major axis, inclination

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3
Q

what planet properties can be found - microlensing

A

mass of planet, star-planet separation

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4
Q

what planet properties can be found - direct imaging

A

period, semi-major axis, eccentricity, temperature of planet, spectrum of planet, mass of planet

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5
Q

what planets they work best with - radial velocity

A

massive planets, close to the star

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6
Q

what planets they work best with - transit

A

large (size wise) planets, CLOSE TO STAR

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7
Q

what planets they work best with - microlensing

A

massive planets, far away from their host star, free floating planets

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8
Q

what planets they work best with - direct imaging

A

far away from host star, long period, hot, large (radius) planet, also young

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9
Q

Kepler’s first law

A

The orbit of a planet is an ellipse with the Sun at one of the two foci.

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10
Q

Kepler’s second law

A

A line segment joining a planet and the Sun sweeps out equal areas during equal intervals of time

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11
Q

Kepler’s third law

A

The square of the orbital period of a planet is proportional to the cube of the semi-major axis of its orbit

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12
Q

Gravitational equilibrium

A

energy supplied by fusion maintains the pressure that balances the inward crush of gravity

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13
Q

describe Hertzsprung-Russel diagram

A

surface temp (x) vs luminosity (y). shows starts from the “main sequence” and there lifetimes

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14
Q

nuclear fission vs nuclear fusion

A

fission: split nucleus into smaller pieces (think nuclear power plants)
fusion: small nuclei stick together to make a bigger one (like the sun and stars)

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15
Q

suppose the mass of the star were less, would luminosity:

A) higher, B) same, C) less

A

less. less mass -> less matter pressing down on the center due to gravity, which means less pressure at the core -> lower rate of fusion

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16
Q

What happens when the star runs out of fuel?

A

Contracts then expands

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17
Q

the two fundamental forces at play in atomic nuclei

A 
electrical forces (protons have the same charge so they repel each other) 
Strong force (protons and neutrons stick together when very close like velcro)
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18
Q

What is a start cluster and what is the significance

A

All stars formed at roughly the same time, all have the same age

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19
Q

helium fusion

A

with enough pressure and heat, helium will fuse into carbon

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20
Q

why are they called “planetary nebula” if they are stars

A

The center of the nebula, the contracted core of the former red giant, is about the size of the earth

that core is hot and dense (mass of the sun in the side of the earth) - think white dwarf

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21
Q

how do supergiants form

A

fusions of higher atomic number elements i.e. iron to silicone to O, NE, magnesium to carbon to helium to hydrogen to nonfusing hydrogen

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22
Q

what’s a supernova

A

. The brilliant point of light is the explosion of a star that has reached the end of its life, otherwise known as a supernova

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23
Q

if a supernova remnant, or planetary nebula has interacts with the cloud….what’ll happen?

A

it can set off a star formation! the fusion products in stars are recycled into new stars

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24
Q

how does a cloud collapse

A

when gravity overcomes pressure

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25
angular momentum = ?
l = mrv, mass*radius*velocity
26
The nebular theory of star and planet formation
Step 1: an over density in a cloud of gas in space causes a piece to collapse from gravity step 2: dust and ice in the dis clump together due to gravity, clumps are called planetesimals step 3: objects at farther distances are more massive because of the availability of rock and/or ice step 4: The rock/ice planetesimals far from the star are more massive, and start to grab the gas around them, forming gas giant planets Step 5: Eventually all the gas is gone, and you are left with a solar system, where....
27
what is accretion
grabbing gas
28
which is more massive, which is more dense between mars and mercury
mars is more massive, mercury is more dense
29
nebular theory summed up
planets for in place from: dense material close to the star more material far from the star (far planets can accrete gas become gas giants)
30
issues with nebular theory
mercury is denser than mars but not part, mars is more massive than mercury but not earth and venus
31
51 peg b
first exoplanet orbiting a sun like star (doppler method) | hot jupiter
32
what is δ
it is the "transit depth" or the "eclipse depth" ratio of areas (area of planet/ area of star circle)
33
δ is ratio of
since the pi's are canceled out in the areas it is really the ratios of: radius of planet squared over radius of the star squared
34
transit probability
(for a circular orbit) p = Rad of star/a
35
What do we learn from doppler?
Orbital period Msini which is the min mass of the planet semi major axis (keepers 3rd law) eccentricity
36
What do we learn if we have BOTH transits and Doppler?
inclination = true exoplanet mass with planet mass and radius we can get average density with density we can make assertions about the interior
37
what is the 55 CNC the star
the bogus diamond planet, it's measured to have excess carbon in its atmosphere
38
describe the nuances Mass-radius diagram
they capture the transition from rocky planets to gaseous planets (since points are density points)
39
What is the Rossiter-McLaughlin effect?
spectroscopic phenomenon observed when either an eclipsing binary's secondary star or an extrasolar planet is seen to transit across the face of the primary or parent star.
40
Rossiter-McLaughlin effect
some planets orbit OPPOSITE to the rotation of their host star
41
two theories for hot Jupiter formation (disk migration and eccentricity migration) - eccentricity migration
start with a normal Jupiter (like ours) a distant third body (nearby star or long period massive planet) tugs on the Jupiter every time it orbits over time, this can "pump up" the eccentricity of the Jupiter, near 1.0, and in some cases cause it to flip eventually the Jupiter circularizes close to the star via tides
42
General relativity
Everything has the same acceleration
43
Einstein's equivalence principle
suppose they were truly equivalent, all laws of physics are the same in both rooms -> then all phenomena are the same
44
Einstein's equivalence principle continued
Perhaps gravity is not a force in the newtonian sense. The only force is from the floor on you, and the floor is stopping you from moving naturally through space. so instead of being a force, gravity is a change in space (and time) itself! mass warps space and time to change how things move in absence of other forces newtonian gravity becomes Einstein's general theory of relativity
45
rubber sheet analogy
4 dimension hyper surface, where time is warped
46
gravitational microlensing
"source" star: background star that gets brighter, usually and intrinsically bright star "lens" star: foreground star that bends light from the background star, usually intrinsically faint star, moves across the light of sight to the back ground star
47
can you see the Einstein ring with microlensing
with microlensing, the Einstein ring is not big enough to be resolved with a telescope
48
downsides to microlensing
you don't measure the orbit of a planet, only its location during the lensing event the lens stars are intrinsically faint and very difficult to study after a planet has been found
49
upsides to microlensing
can be used to find rogue planets
50
Direct detection
need to suppress the light from the star in order to directly see any orbiting planets
51
what is a coronagraphy
block out the light from sun/star to see the fainter things around it
52
starlight suppression facts (direct imaging really)
turbulence in the earth's atmosphere "seeing" makes it very difficult to block the starlight without also blocking from the planets! there is blurring due to the earth's atmosphere
53
another way to get around the earth's atmosphere
adaptive optics: rapidly change the shape of a mirror to remove blurring
54
adaptive optics coronagraphy
telescopes on the ground are bigger than telescopes in space allow you to collect more light from star so far, found about a dozen planets
55
what are the easiest planets to detect with direct imaging?
bright ones that are far from their host stars needs that reflected light
56
total reflected light depends on what
luminosity of the star planet-star distance planets' size planet albedo
57
total light vs contrast
since the main challenge to direct imaging is starlight suppression, total light from a planet isn't as important as the contrast
58
emitted light
it will emit it's own radiation in the infrared if the planet is young, it is still hot from formation
59
direct imaging
nearly all planet found with D.I. are orbiting young stars | planets are also young themselves
60
starshade
blocks the star in the camera, less scattered light, used to enhance detecting planets around the star
61
what is the habitable zone?
s the range of orbits around a star within which a planetary surface can support liquid water given sufficient atmospheric pressure
62
what properties of a planet determine whether it is potentially habitable?
WATER FAM | Temp and pressure on the real
63
how does the habitable zone change with stellar type?
size of the star (& amount of heat it gives off) affecting the distance from the star that the habitable zone is
64
an orbital distances where life could definitely exist on a planet?
NO
65
Orbital distances where liquid water could persist on the planet's surface?
YES JABRONI it's important cuz all living life that we know of requires that WATER. but we don't know whether it is actually needed for all life. Thanks ugly god
66
energy balance
energy incident on a planet equals energy embittered by the planet energy in = energy out a planet must off as much as it receives, otherwise it builds up that energy and explodes!
67
how much star light is incident on the planet?
flux @ planet = (star luminosity)/4pi(distance)^2
68
how much absorbed light by the planet
absorbed light = flux @ planet * pi(planet rad)^2 * (1-albedo)
69
how often is energy balance
every second fam
70
light emitted is dependent on
temperature | higher the temp, more total emission, the bluer the light
71
the greenhouse effect
absorption lines from gases in the planet's atmosphere force the planet to be even hotter to meet energy balance
72
what determines the pressure of the atmosphere
well, there is no single pressure, it is constantly changing throughout the atmosphere
73
what determines the height of the atmosphere
temp(T) * Boltzmann constant(k) = mean molecular mass (mu) * acceleration(g)
74
pressure at surface?
determined by the ideal gas law P=nkt n= number density of molecules k=boltzmann constant t=temp
75
can mars have water
kinda, pressure is too low to retain water so it evaporates immediately
76
what's a "super earth"
a planet with a mass between Earth and Neptune
77
why do hot Jupiters give a flat transmission spectra
low scale height (H is small, high mu) (mu= molecular mass) CLOUDS
78
why clouds?
cuz they be blocking all the wavelengths equally
79
biosignatures?
indicators of life
80
what would they even look lie?
treat earth as an exoplanet On earth, oxygen in the atmosphere is produced entirely by life methane is produced by life and some geological outgasin (CH4) together, they quickly burn to become CO2 and H2O
81
Transit Transmission
Primary eclipse. Planet passes in front of star.
82
Secondary Eclipse
Secondary eclipse. Star passes in front of planet.
83
The light that is blocked by the star during secondary eclipse comes from:
day side
84
the power of secondary eclipse and phase curves
directly measure exoplanet temperatures, compare to expected to study greenhouse effects measure day/night side contrast infer the presence of global winds can measure albedo at visible wavelengths
85
what determines the depth (transit vs secondary eclipse)
transit: radius ratio of the planet to the star secondary eclipse: radius ratio of the planet to the star AND the planet's light (emission or reflection)
86
what types of exoplanets is easiest for secondary eclipse detection
easiest for large, hot (hot Jupiters) | hardest for small, cold
87
James Webb Space Telescope
successor to Hubble, much larger mirror, Can detect Ozone feature in absorption during secondary eclipse of a super-earth orbiting within the habitable zone of an M dwarf star
88
O3 Ozone
Ozone is opaque to UV, protects our ass. considered to be the deepest expected biosignature. biotic o2 rises, UV radiation splits the molecule, recombines to form O3.
89
So this shit indicates plant life, what about that intelligent life? Search for extraterrestrial intelligence (SETI)
extraterrestrial intelligence will create deliberate or accidental signals that enable communication with life on other planets in the galaxy and universe
90
best wavelength for transmission
21cm (microwaves), it can survive atmosphere (found by cocconi and Morrison)
91
Search for signals that indicate extraterrestrial intelligence:
Deliberate: intended to reach other worlds accidental: unintended, but nevertheless reveal technology
92
what's the strongest accidental
Radar
93
deliberate?
prime numbers, groups of large primes are hard to get naturally
94
Arecibo transmission
lot of number, 1 to 10 in binary, atomic numbers of HCNO and P which are elements in DNA...formulas for molecules in DNA, Image of DNA, Graphic of a human, graphic of the solar system, image of Arecibo telescope
95
2017 solar eclipse
total solar, aug 21, viewable from high pop centers in the US

alien worlds (4 decks)

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