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53 Cards in this Set

  • Front
  • Back
Light as a wave
Electric and magnetic fields that travel=Electromagnetic wave
What EM waves can human eyes detect?
Light as a particle (photon)
Photon energy is proportional to 1/wavelenth
Longer wavelength equals...
less energy
The electromagnetic spectrum
Gamma ray, xray, ultraviolet, visible, infared, microwave, radio
Two atmospheric windows
visible, radio
Telescopic Functions
Light gathering Power
Resolving Power
Magnifying power
Issac Newton
Cut a slit in a curtain and passed the light through a prism for the colors
Passed light through curtain onto a diffraction grating and found dark lines. Labeled them.
Bunsen and Kirchoff
Passed light through heated chemicals and found bright lines. Discovered sodium on the sun
Kirchoff's 1st Law
If light passes through a hot, hig density solid, liquid, or gas, you get a continuous spectrum
Kirchoff's 2nd Law
Hot, low density gas gives off a bright line spectrum
Kirchoff's 3rd Law
Source of continous spectrum light passes through a cooler, low density gas creating a dark line spectrum
Spectral lines are due to atomic electrons changing energy levels
Photons are Absorbed
dark line spectrum
Photons are Emitted
Bright Line Spectrum
Balmer Series
Electrons jumping up or down from energy level 2
apparent change in an objects position due to a change in the observers location
Parallax Method
distance in parsecs=1/parallax angle in arc seconds
Parallex Measurements Largest to smallest
0.77 arc sec-0.002 arc sec
Apparent Magnitude
how bright a star appears to be (negative is brighter)
Absolute Magnitude
measure of the light output of a star
When does (m) = (M)?
When the distance is 10pc
Range of M for stars
-10 to +20
measure of the light output of a star
Rangle of L for stars
10 to the power of 6-10 to the power of -6
Proper Motion
motion perpendicular to the line of sight-moving side to side
Radial motion
motion along the line of sight-moving toward or away
Doppler Effect-Moving towards
Moving away
Black Body
hot solid, liquid, or a hot, high density gas
Black Body Radiation
light emitted by a hot object
Wien's Law
temperature is proportional to 1/wavelength max
What is Wien's law saying?
cool stars are red, hot stars are blue
Stefan Boltzmann Law
L is proportional to radius squared * temperature to the fourth power
Are stars black bodies?
Almost, they have valleys in the dark line
What type of spectra does a star give off?
A dark line
What can we find from a stars spectrum?
Chemical Composition
Radial Motion
Surface Temperature
Chemical composition
by line patterns
Radial Motion
Shift in line patterns
Surface Temperature
strength of spectral lines
Stellar Spectral Types
Hertzsprung-Russell Diagram
M vs. Spectral Type
Stellar Size
Stefan Boltzmann law-range from 0.01R Sun-1000R Sun
Stellar Mass
mass a/mass b=distance b/distance a
Newton's form of Kepler's 3rd Law
mass a + mass b= a AU cubed/P years squared
Range of masses
0.08 solar masses-100 solar masses
Stellar density range
10 to the -6g/cm cubed-10 to the 7 g/cm cubed
Innerstellar Medium Composition
3/4 hydrogen, 1/4 helium, 2% heavier elements
ISM Density
1 atom/cm cubed
Giant Molecular Clouds density, size, and temperature
100 atoms/cm cubed
Hydrostatic Equilibrium
balance between inward gravity and outward energy released from fusion
How do stars form
Shockwave goes through giant moecular cloud creating dense cores. Gravity starts to collapse these dense cores. A protostar (nucleus) forms in the dense core. Protostar gives off heat and creates energy. Hydrostatic Equilibrium occurs.