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Astronomy Flashcards
Robinson 301 UT
59
Astronomy
Undergraduate 1
03/02/2011

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Cards

Term
Speed of light
Definition
3.0 x 10^10
Term
Distance of stars
Definition
1/P
P=Parallax
Term
Brightness
Definition
1/D^2
Term
Wavelength
Definition
λ = v/c
c=frequency
Term
Structure of an atom
Definition
There are electrons, protons, and neutrons
Term
1 parsec =
Definition
206,265 AU
Term
1 parsec also equals
Definition
3.26 ly
Term
Proper motion
Definition
the motion of a star across the sky
Term
Luminosity
Definition
intrinsic brightness
Term
The luminosity of a star is...
Definition
the amount of energy it radiates each second into space
Term
1 solar luminosity=
Definition
1 L
Term
The more distant an object...
Definition
the fainter it appears
Term
Light is...
Definition
a photon. Sometimes it acts as a wave sometimes as a particle.
Term
1 Angstrom =
Definition
1 x 10^-8 cm
Term
Speed in terms of waves is
Definition
the rate at which the peaks move
Term
Frequency
Definition
is the number of peaks per second that passes the observer
Term
λ(frequency) =
Definition
speed
Term
frequency is(in the equation)
Definition
λ/speed
Term
Light is
Definition
a vibrating electric field
Term
a wave in electric and manetic fields is...
Definition
light!
Term
Electromagnetic radiation is...
Definition
light is a form of it.
Term
Temperature measures...
Definition
the speed at which the particles move
Term
Kelvin temperature =
Definition
celsius temper + 273
Term
Kirchoff's First Law
Definition
a hot solid, liquid, or opague gas emits light at all wavelengths, producing a continuos spectrum
Term
Anything that is hot...
Definition
emits light.
Term
Black body radiation is...
Definition
the ideal case for radiation
Term
The energy emitted by a black body
Definition
increases rapidly with temperature
Term
Neutral Atoms
Definition
have the same number of protons and electrons
Term
Ionized atoms
Definition
are missing one or more electrons
Term
Atoms are ionized by
Definition
collisions with other atoms
Term
Atoms are more likely to be ionized in
Definition
Hot gases because atoms move more rapidly when the temperature is high. Atoms are moving more rapidly, collisions are stronger. Ionization is more likely stronger collisions. So ionization is more likely at higher temperatures.
Term
Energy of an electron is...
Definition
greater in upper orbits.
Term
Photon
Definition
is a particle of light
Term
photon energy =
Definition
(a constant) x (wave frequency)

the equation is E=hv
Term
h is planks constant
Definition
Term
frequency =
Definition
speed/wavelength

v = c/λ
Term
When an electron jumps from a higher to a lower energy level,
Definition
a photon appears and carries away the difference
Term
in black body radiation λ max =
Definition
2.9 x 10^7/ T
Term
Temperature of a star
Definition
can be measured from their spectral type, from their color, and from the wavelength of the peak in their continuous spectra.
Term
black body
Definition
is something that absorbs all the light falling on it.
Term
when a blackbody object is heated...
Definition
it emits light very efficiently without any gaps or breaks in the brightness
Term
Kirchoff's second Law
Definition
a hot, rarefied gas emits light at discrete wavelengths, creating an emission line spectrum.
Term
Kirchoff's 3rd law
Definition
if light with a continuous spectrum pass through a cool, low density gas, the gas removes light at discrete frequencies, producing an absorption line spectrum.
Term
Temperature for spectral type O
Definition
>30,000K
Term
Temperature for spectral type B
Definition
15,000K
Term
Temperature for spectral type A
Definition
9,000K
Term
Temperature for spectral type F
Definition
7,000 K
Term
Temperature for spectral type G
Definition
5,500 K
Term
Temperature for spectral type K
Definition
4500K
Term
Temperature for spectral type M
Definition
3000 K
Term
for the doppler effect v/c
Definition
λ-λR/λR
Term
objects radial velocity/speed of light =
Definition
change of wavelength/ rest wavelenth
Term
Hertsprung-Russel Diagram
Definition
Each dot represents a single star
Term
In the HR(Hertzsprung Russel) Diagram why do we put the low on the right and the high on the left?
Definition
Because of luminosity. The position of the dot is set by the stars luminosity and temperature. We do this for lots of stars. Every time we get this we put a dot on the diagram. The dots fall into clumps. The most important one is the one that goes from the upper left to the lower right.
Term
Density =
Definition
Mass/Volume
Term
White dwarf sequence include about _ of all stars
Definition
7%
Term
Red Giants are _ of all stars
Definition
3%
Term
Super giants
Definition
are extremely rare and can have a luminosity of 10^6 times greater than the sun.
Term
Excitation-
Definition
electrons are normally found in there lowest level because they spontaneously jump to lower levels. But they do take time to jump, so they can sometimes be found in a higher level than normal.
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