astronomy exam 3 Flashcards
What are two ways atoms get excited
Collision among atoms, photon of correct energy gives energy to an atom
two types of spectra
Absorption and emission
emission
See photons who are readmitted
higher radiation
higher temperature
lambda max
Wavelength where radiation curve has highest energy
intensity
Energy per unit time per unit area
doppler effect
Sound waves move differently when they are coming towards or away from you, sound is artificially compressed
longer wavelength =
red / shorter wavelength = blue
granules and sunspots
are features of the photosphere
spicules
chromosphere features
solar wind
Charged particles emitted from sun
zamon effect
helps remotely sense magnetic fields, sun spots have strong magnetic fields
plasma
highly ionized fluid
sun rotations
moves faster in its equator differential rotation
Kepplers law of planetary motion
p^2/a^3
coulomb force
repulsive force between particles with electrostatic charge, nuclear resistance to collisions reactions only at suns center
binding energy
energy needed to pull electron away
permitted orbits
One of the energy levls in atom that elecctrons may occupy
ground state
Lowest permitted electron orbit of atom
excited atom
moves from low to high energy levels
thermal energy
energy from agitation
blackbody radiation
radiation emitted by heated object made up of photons with distribution of wavelengths
stefan boltzwan law
mathematical relation between temp of black body and energy emitted
weins law
lambda max = 2.90 x 10^6/T(k)
balmer series
only 3 hydrgen lines in what series are visible
doppler effect
change in wavelength of radiation caused by motion of source
nuclear fusion
combine light nuclei, net energy
how much mass converts into energy
e=mc^2
for fusion to occur
there needs to be high temperature and high density
v-neutrino
subatomic particles that don’t like to interact
parallax
position relative to other stars can change depending on our orbit
intrinsic brightness
actual brightness distance effect accounted for
luminosity
total ammount of energy a star emits every second
spectral classification
use specture of star to determine the temperature of the star absorption line strength of carious elements allows temperature to be found
spectropic parallax
finding distance to star using spectrum
binary star system
center both orbits is center of mass at the center
types of binary star systems
center both orbits is center of mass at the center
visual system
observable through telescope as two stars.
spetroscopic
look at spectrumm evidence that there are two stars
eclipsing binary
orbital plane close to parallel to our line of sight dips in intensity when one blocks the other, total brightness is dimmed
supernova explosion
shockwave hits gas and dust regions w cloud becomes more dense.
protostar
lump in gas and dust cloud that becomes star because it is compressed and hot enough to be opaque to radiation and not go through nuclear
cocoon
is the dust and gas around the protostar
young stellar objects,
cocoon is gone so the protostar is more visible
parrralc
is a shift in star position
stellar parallax
shift of a star observed form 1 au baseline
parsec
distance to imaginary star wit a parallaz of one arc second
visual binary
is when two separate stars are visible on a telescope
spectroscopic binary
are two stars that are too close together to be seen as separate visually
spectroscopic parallax
finding distance by comparing apparent magnitude with absolute magnitude
degenerate matter means
electrons groups together and dont let size of the core to change
planetary nebula
in medium stars when outer layer of core begins to drift away
core remnant
what remains all fusion stops
compact object
not actually a star anymore after star cools
white dwarf
what’s left of medium mass star after it dies, it has low luminosity because it has low surface area
Chandreshhar limit
mac amount of mass white dwarf can have while remaining white dwarf
why do sunspots appear dark?
they appear dark because of convection occurring near them leaving cool spots, on the surface. Because they are cool, they emmit less light and appear dark
what conditions must be met for fusion to occur and be sustained?
temperature must be high enough, pressure must be high enough
which object would have the most narrow absorption lines main sequence star, giant star, supergiant star
super giant
where are granules found?
granules are areas new the surface caused by convection. They’re found in the photosphere
what is happening in the core of the sun that generates energy
fusion
is the average number of sunspots visible on the sun the same year after or not?
No, the average number of sunspots visible on the sun is not the same year after year. The number of sunspots visible from Earth changes daily and in cycles that can last for decades, centuries, or millennia. The most well-known cycle is the 11-year sunspot cycle, where the average number of sunspots increases and then decreases over the course of 11 years.
explain how astronomers can estimate the luminosity of a star from its spectrum
Astronomers can estimate a star’s luminosity by analyzing its spectrum to determine its spectral type and luminosity class. A star’s spectrum of light appears as a color to the human eye, and the color is a good indicator of its brightness
method used in spectroscopic parallax
- Fin the temperature of the star
- Use luminosity classification to estimate luminosity
- use H-R diagram to find Mv
- observe to find m
- fo the math to find d
