Quiz 2 Flashcards
Split sunlight with prisms, created larger prism in 1800s that could observe 574 dark lines in continuous spectrum. Combination prism and telescope allowed spectra moon, mars, Venus, later used diffraction gratings
Newton/Fraunhofer
Can be thought of as electromagnetic waves, periodic disturbances of electric/magnetic fields. Color is frequency, brightness is height of crest
Nature of light
Radio waves, infrared, visible, ultraviolet, x rays, gamma rays
EM scale
Blocks radiation other than radio, visual, and some UV/infrared
Earth’s ozone layer
Distribution of wavelength
Spectra
An object emits electromagnetic radiation if its temperature is above absolute zero
Thermal spectra
T x ymax=constant, determines max wavelength
Wein’s law
only electromagnetic radiation of frequencies unique to substance producing light. Colored lines
Emission spectrum
Dark lines in a continuous thermal spectrum, occurs when a continuous source of light passes through material like cold gas
Absorption spectrum
Light can behave like waves or a particle with no mass photon. When an electrons orbit is changed with a receiving of energy
Why spectrum works
CNatures way of getting packets of energy from one place to another
Light
An atom with one electron and one proton. The electron doesn’t need to climb to first energy state only, can by absorbing energy to climb to higher states
Bohr’s model
Applied to any main sequence star for which a spectrum can be recorded (star must be bright, reliable up to 10k pc)
Spectroscopic parallax
could only go out 500-1000pc
Parallax
Director of Wilson observatory, studied spectral and attempted to correlate spectral lines to absolute magnitude
Walter S Adams
Walter’s assistant
Ernst Kohlshutter
Relates numbers and difference of spectral lines/different stars as well as temperature. Discovered by Annie Jump Cannon
Harvard college observatory spectral classes
Finds the diameter relating to the stars luminosity, radius, and temperature
Stefan Boltzmann law, L/L=R/R(T/T)^4
Discovered a relationship between spectral classes and luminosity of stars, plotted this, and found the relationship.
Hertzprung and Russel
Large yellow stars, less than 700. Periods ranging 3-50 days, radiates 10k as much energy as the sun, brightness varies .01-2 mangitude
Cepheid variable stars
Low amplitude cepheid variable
Polaris
Investigated 100s of Cepheids in Magellanic clouds, discovered the brightest cepheids always had longest periods, and correlated its median luminosity (absolute magnitude) with their period
Henrietta Leavitt
Discovered variable stars in the whirlpool nebulae, and that galaxies are moving away from us
Hubble
Established nebulae were external galaxies far away
Period luminosity relationship
Can be observed 30 or so in the nearest galaxies and serve as a rung on the cosmic distance estimation ladder
brightest cepheids
From earth, 2.5 times brighter than next highest magnitude
Apparent brightness
10pc from the sun observed
Absolute magnitude
Masses from .1-200m, luminosity 10^-6-10^6L, temperature 1/3-100T, radii 1/100-100R
HR diagram
Normal, 90%, 1-70M. Hot, dense cores that produce energy from hydrogen and helium
Main sequence stars
Small and hot, bottom left, peculiar. MS after using up nuclear fuel
White dwarf
Large and cool, middle right, peculiar. In the final stages of stellar evolution, our star will become this
Red giants
Large and cool, top, peculiar. Develop when MS runs out of hydrogen
Supergiants
Search for causes, astrophysics
Stellar structure
Spherical hot gas in equilibrium, density light but gaseous
Stars
Nt, governs gravitational once, thus condition of equilibrium. Stars on the MS identical in composition, different temperature, diameter, and luminosity due to mass
Mass
Source of stellar energies, proton-proton or carbon cycle
Nuclear reactions
Departs from here when hydrogen is used up. Will not remain static, will change
Main sequence leaving
Uses proton proton cycle and stays for billions of years
Low mass
Uses carbon cycle and will leave in a million
High mass stars
A supernova from a star up to 50 times the mass of the sun. Comes from the rapid collapse
Type 2 supernova
Takes matter from a neighboring star until a nuclear reaction is triggered
Type 1 supernova
American astronomer who provided high quality photographs and discovered a comet
Milton Humason
Indicate a wider frequency of wavelength in the radiation of an object due to emission or absorption
Broadening spectral lines
Indicator of whether a star or galaxy is moving towards or away from us, with light stretching blue when towards and red when away
Doppler effect
Wavelength of stars and galaxies are stretched to red, meaning that space is expanding
Cosmological redshift
Splitting a spectral line into two or more different frequencies when in a magnetic field
Zeeman effect
