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Final
astronomy 191 final material
79
Astronomy
Undergraduate 1
12/14/2011

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Cards

Term
full moon
Definition
earth between moon and sun
Term
new moon
Definition
moon is between earth and sun
Term
why solar eclipses?
Definition
because of same angular distance of 0.5 degrees
Term
why lunar eclipses?
Definition
b/c moon's orbit is tilted and shadows miss each other
Term
retrograde motion
Definition
as earth catches up to the orbital motion of another planet, that planet seems to move backwards through the sky
Term
superior conjunction
Definition
in front of sun
Term
inferior conjunction
Definition
between sun and earth
Term
opposition
Definition
behind earth
Term
Kepler's first law
Definition
planets have elliptical orbits around sun
Term
eccentricity
Definition
how stretched out an ellipse is
the higher (closer to 1), the flatter the ellipse
Term
Kepler's 2nd law
Definition
planets move faster when near the sun and slower when farther from the sun
Term
kepler's 3rd law
Definition
P^2=a^3

P- period a- orbit size
Term
Newton's 1st law
Definition
body at motion tends to stay in motion unless forces acting on it
Term
Newton's 2nd law
Definition
F=ma
Term
Newton's 3rd law
Definition
for ever action there is an equal and opposite reaction
Term
g(planet)=GM/R^2
Definition
surface gravity equation
Term
if something travels at exactly the escape velocity, it leaves in a ______ trajectory
Definition
parabolic
Term
if something travels at more than the escape velocity, it leaves in a _______ trajectory
Definition
hyperbolic
Term
the color of light is determined by its ______
Definition
wavelength
Term
the higher/lower the frequency, the higher/lower the energy
Definition
higher-higher
lower-lower
Term
quantized
Definition
exist only at very particular energies
ex: electron orbits and photons
Term
electronic transitions
Definition
electron moves to a lower orbital
specific amount of energy
Term
atomic number
Definition
number of protons in a nucleus
Term
absorption
Definition
if photon of exactly right amount of energy strikes an electron, that electron will absorb the photon and move to the next higher orbital
Term
ionized
Definition
electron gains enough energy to leave the atom entirely
Term
if atom drops from one orbital to the next lower one, it must first...
Definition
...emit a photon with the same amount of energy as the orbital energy difference
Term
wavelength
Definition
distance between two crests
Term
long/short wavelength light has a high/low frequency
Definition
long-low
short-high
Term
long wavelength photons carry less/more energy than short wavelength ones
Definition
less
Term
electromagnetic spectrum
Definition
radiowaves
microwaves
infared
visible
ultraviolet
x-rays
gamma rays
Term
blackbody
Definition
body that absorbs all photons and emits energy of all wavelengths
Term
wien's law
Definition
the hotter a body is, the more strongly it will emit at shorter wavelengths
Term
Stefan-Boltzmann law
Definition
the luminosity of a hot body rises rapidly with temperature
Term
when an electron moves from one level to another, it must absorb or emit an amount of energy equal to the _____ between the energy levels it enters
Definition
difference
Term
if object is moving away from you, the light will be ____-shifted
Definition
red
Term
red-shifts have____ wavelengths
Definition
longer
Term
blue-shifts have _____ wavelengths
Definition
shorter
Term
the lorentz factor
Definition
matter contracted while it was moving, reducing its length in the direction of motion
Term
at slow speeds, the effect of the lorentz factor is ____
Definition
small
Term
red-shirts have ____ frequencies
Definition
lower
Term
blue-shifts have _____ frequencies
Definition
higher
Term
wein's law
shorter wavelengths= ______ body
Definition
hotter
Term
wein's law
longer wavelengths= _______ body
Definition
cooler
Term
wein's law
hotter body= _____ wavelengths
Definition
shorter
Term
wein's law
cooler body= _____ wavelengths
Definition
longer
Term
meteor
Definition
moves through earth's atmosphere
Term
meteroid
Definition
before atmosphere
Term
meteorite
Definition
reaches ground
Term
planet's mass and radius affect its
Definition
interior temperature and tectonic activity
Term
low mass, small radius planets cool ______
Definition
faster
Term
structure of sun
Definition
corona- sun's outer atmosphere
chromosphere- sun's lower atmosphere
photosphere- sun's visible surface
convection zone
radioactive zone
core
Term
in sun, gravity pulls ____, pressure pushes ____
Definition
inward, outward
Term
hydrostatic equilibrium
Definition
the outward pressure force must balance the inward gravitational force of every distance from the center of the sun
Term
coronal holes
Definition
regions of low magnetic field in sun
Term
fusion
Definition
merging of hydrogen nuclei into helium
Term
products of proton-proton chain
Definition
energy and neutrino
Term
neutrino
Definition
low mass, high energy particle
Term
if star is 2 parsecs away, its parallax is
Definition
1/2 arcseconds

b/c 1/parsecs
Term
if star is 1/2 parsecs away, its parallax is
Definition
2 arcseconds

b/c 1/parsecs
Term
if star is 1 parsec away, its parallax is
Definition
1 arcsecond

b/c 1/parsecs
Term
1 parsec= ___ ly
Definition
3.26
Term
radial velocity
Definition
speed of a star's motion toward or away from the sun
Term
stellar luminosity

if you go away from a star by 10, the brightness will go down by _____. why?
Definition
100

b/c 10^2 (inverse square law)
Term
hotter star letter

cooler star letter
Definition
O, M
Term
visual binary
Definition
binary stars seen from pictures taken
Term
spectroscopic binary
Definition
stars are so close together that their spectra blur together
Term
eclipsing binaries
Definition
one star with periodically eclipse the other star
Term
speckle interferometry
Definition
uses multiple images from the same telescope to combine them and make a picture to see details of star better
Term
trends of HR diagram
low-mass main sequence stars tend to be ____ & _____
high-mass main sequence stars tend to be ____ & _____
Definition
cooler and dimmer

hotter and brighter
Term
evolution of low-mass star
Definition
interstellar cloud
protostar
sun today
red giant
yellow giant
2nd red giant
planetary nebula
white dwarf
Term
a white dwarf is ____ size of the current sun
Definition
1/100th
Term
evolution of high-mass star
Definition
interstellar cloud
protostar
blue giant
yellow giant
red giant
supernova
neutron star or black hole
Term
the core density of a high-mass star is ___ than that of a low-mass star
Definition
less
Term
low-mass stars rely on the ____ for internal energy
high-mass stars rely on the ____ for their internal energy
Definition
proton-proton cycle
CNO cycle (carbon, nitrogen, oxygen)
Term
when star enters red giant phase their atmospheres expand/contract and their core expands/contracts
Definition
atmosphere-expand
core-contract
Term
when star enters red giant phase their atmospheres become hotter/cooler and their core becomes hotter/cooler
Definition
atmosphere-cooler
core-hotter
Term
a ____ cephid pulsates more slowly
Definition
brighter
Term
a _____ cephid pulsates more quickly
Definition
dimmer
Term
if mass added to a white dwarf, radius ____, density ____, and electrons gain ____ energies
Definition
radius stays same
density increases
electrons gain higher energies
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