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Coulomb force
The electrostatic force of repulsion or attraction between charged bodies
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binding energy
The energy needed to pull an electron away from its atom
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quantum mechanics
The study of the behavior f atoms and atomic particles
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Permitted Orbit
One of the energy levels in an atom that an electron may occupy
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Black body radiation
Radiation emitted by a hypothetical perfect radiator
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Wavelength of maximum intensity
The wavelength at which a perfect radiator emits the maximum amount of energy; depends only on the objects temperature.
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Joule
A unit of energy equivalent to a force of 1 newton acting over a distance of 1 meter
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continuous spectrum
A spectrum in which there are no absorption or emission lines
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absorption spectrum
A spectrum that contains absorption lines caused by photons being absorbed by atoms or molecules
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absorption line
a dark line in a spectrum; is produced by teh absence of photons absorbed by atoms or molecules
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emission spectrum
a spectrum containing emission lines
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emission line
a bright line in a spectrum caused by the emission of photons from atoms
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Kirchhoff's laws
A set of laws that describe the absorption and emission of light by matter
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transition
the movement of an electron from one atomic energy level to another
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Lyman series
Spectral lines in the ultraviolet spectrum of hydrogen produced by transitions whose lowest energy level is the ground state
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Balmer series
A series of spectral lines produced by hydrogen in the near ultraviolet and visible parts of the spectrum
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Paschen series
Spectral lines in the infrared spectrum of hydrogen produced by transitions whose lowest energy level is the third
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radial velocity
A component of an object's velocity directed away from or toward Earth
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isotope
An atom that has the same number of protons but a different number of neutrons
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Ion
An atom that has the same number of protons but a different number of electrons
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How to permitted energy levels of the electron allow us to identify a specific element?
The transitions for the electron energy levels produce specific wavelengths to identify specific elements, like a fingerprint
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Why are titanium oxide bands produced in stars cooler than 3000 K?
If it were any hotter the temperatures would not allow the molecules to stay bonded
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Why does the Doppler effect only find the radial velocity?
You cannot use the doppler effect to detect any part of the velocity that is perpendicular to your line of sight. It is only sensitive to the part of the velocity directed away from you or toward you.
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What is an ion and how is it formed?
An ion is an atom with an electric charge. The atom can either gain or lose one or more electrons.
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Filaments
Solar prominences seen from above silhouetted against the bright photosphere
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spicules
Small, flamelike projections in the chromosphere of the sun
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magnetic carpet
The network of small magnetic loops that covers the solar surface
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Zeeman effect
The splitting of spectral lines into multiple components when the atoms are in a magnetic field.
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differential rotation
The rotation of a body in which different parts of the body have different periods of rotation
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Prominence
A loping eruption on the solar surface of ionized gas trapped in a magnetic field.
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reconnections
On the sun, the merging of magnetic fields to release energy in the form of flares.
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Coronal mass ejections
matter ejected from the sun's corona in powerful surges guided by magnetic fields
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Why are sunspots cooler than the surrounding surface?
The strong fields are believed to inhibit gas motion below the photosphere;p consequently, convention is reduced below the sunspot, and the surface is cooler
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What causes the dynamo effect?
A magnetic field is produced when a rapidly rotating conductor is stirred by convection
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Why would astronauts on the moon or Mars be concerned about solar flares?
The moon and Mars lack significant magnetism and would not protect astronauts from many of the particles released by the sun during a flare
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Explain how scientists probe the sun's interior by detecting neutrinos.
If you can detect neutrinos, you can compare the number of them with the products of theorized thermonuclear fusion.
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Describe how the Babcock model explains the magnetic cycle.
The magnetic field gets captured in the gas and as the sun rotates with differential rotation, the magnetic field gets tangled. When it gets so tangled that it breaks through the surface, you see sunspots.
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Explain how the nature of sunspots led astronomers to the currently accepted theory for the sun's magnetic cycle
Sunspots always come in pairs and the polarity reverses in each solar sunspot maximum. Using the Zeeman effect, we could tell that sunspots were magnetic
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Flux
A measure of the flow of energy out of a surface, usually applied to light
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Light curve
A graph of brightness vs. time
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Parsec
The distance to a star whose parallax is one second of arc.
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Kepler's first law
The orbits of the planets are ellipses that are very nearly circles
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Keplers second law
An imaginary line drawn from the planet to the sun always sweeps over equal areas in equal intervals of time
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Keplers third law
A planet's orbital period is related to its average distance from the sun
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Newtons first law of motion
A body continues at rest or in uniform motion in a straight line unless acted upon by some force.
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Newtons second law of motion
The change of motion of a body of mass is proportional to the force acting on it and is in the direction of the force
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Newtons third law of motion
When one body exerts a force on a second body, the second body exerts an equal and opposite force back on the first body
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Spectral classes from hottest to coldest
O, B, A, F, G, K, M
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Luminosity Class Ia
Bright Supergiant
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Luminosity Class Ib
Supergiant
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Luminosity Class II
Bright giant
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Luminosity Class III
Giant
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Luminosity Class IV
Subgiant
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Luminosity Class V
Main-Sequence star
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What does a light curve measure?
brightness vs. time
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What is the most common spectral class of main-sequence stars?
Class M
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Spectral class O
40,000 K Weak Balmer lines
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Spectral Class B
20,000 K Medium Balmer Lines
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Spectral Class A
10,000 K Strong Balmer lines
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Spectral Class F
7500 K Medium Balmer lines
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Spectral class G
5500 K Weak Balmer lines
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Spectral Class K
4500 K Very weak Balmer lines
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Spectral Class M
3000 K Very very weak balmer lines Only stars with Titanium Oxide
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How can you tell which star is hotter by looking at an eclipsing binary light curve?
You can look at the light curve and point to the deeper of the two eclipses and say "That is where the hotter star is behind the cooler star."
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What is the difference between flux, luminosity, and absolute visual magnitude?
Flux is the energy in Joules per second falling on one square meter. Luminosity is how much energy per second a star emits. Absolute visual magnitude is the apparent visual magnitude a star would have if it were 10 parsecs away.
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Why would it be easier to take a parallax measurement if we were on a planet further from the sun than Earth?
The orbit is bigger for planets further from the sun, the baseline would be wider and the shifts would be larger and easier to measure.
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Describe the process of using spectroscopic parallax to determine the distance to a star.
Determine the spectral class and then see the horizontal location on the H-R diagram. You can also determine luminosity by looking at the widths of the spectral lines. Once you plot the point on the diagram, you can determine its absolute magnitude. Absolute magnitude and apparent magnitude can determine distance.
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Why do extremely cool stars look fainter than you might expect with their luminosities and distances?
The coolest stars radiate the vast majority of their photons in the infrared, which you can't see
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What is the difference between spectral class and luminosity class?
Spectral class is based mainly on temperature. Luminosity class is dependent mainly on size. larger stars of the same temperature give off more luminosity than smaller stars.
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How would the spectra from a G2 V star differ from a G2 III?
The stars would have the same temperature, but the difference between them is that a luminosity class V star is on the main sequence and a class III star is a giant star. Therefore, the spectra of a giant star would have a narrower spectrum lines than a main sequence.
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First law of Stellar Structure
Conservation of mass
Total mass equals the sum of shell masses
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Second Law of Stellar Structure
Conservation of Energy
Total luminosity equals the sum of energy generated in each shell
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Third Law of Stellar Structure
Hydrostatic equilibrium
The weight on each layer is balanced by the pressure in that layer
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Fourth Law of Stellar Structure
Energy Transport
Energy moves from hot to cool regions by conduction, radiation, or convection
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Herbig Haro objects
Formed when powerful jets from a newborn star strike the interstellar medium.
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T-tauri stars
Stars that fluctuate in brightness and appear to be newborn stars just blowing away their dust cocoons
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Reflection nebulae appear to be what color?
Blue
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Stars that contract the slowest to land on the zero-age main sequence line on the H-R diagram are the _____ massive
least
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To begin to collapse into stars, an interstellar cloud must be?
Cold and dense
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What two characteristics are balanced in hydrostatic equilibrium?
weight and pressure
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When a star begins its stable life, it begins on the
Zero age main sequence
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Why does the fusion of heavier atoms require higher temperatures than the fusion of hydrogen?
Heavier atomic nuclei have higher positive charges so their Coluomb barrier is higher. This requires that the gas be hotter so the particles move faster and the collisions will be more violent.
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How can very cold clouds make very hot stars?
Gravity causes the cold gas to contract to the point that it turns on its thermonuclear processes
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What would happen if the sun stopped generating energy?
With no pressure to push outward against gravity, it would collapse.
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Describe the difference between a reflection nebula, an emission nebula, and a dark nebula and what spectra would they show, if any.
A reflection nebula is when starlight is scattered in a dusty nebula. It reflects the absorption spectrum of the star. An emission nebula is prouced when a hot star excites the gas to produce an emission spectrum. A dark nebula is a dense cloud of dust and gas that obstructs the view of more distant stars. It produces no spectra
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Conservation of mass
A law of stellar structure. States that the total mass of the star must equal the sum of the masses of the shells.
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Conservation of energy
A law of stellar structure. States that the amount of energy flowing out of the top of a shell must equal the amount coming in at the bottom plus whatever energy is generated within the shell
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Hydrostatic equilibrium
A law of stellar structure. States that the balance between the weight of the material pressing downward on a layer in a star and the pressure in that layer must be equalizing
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Energy transport:
A law of stellar structure. States that the flow of energy from hot regions to cooler regions by one of three methods: conduction, convection, or radiation.
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What temperature does the proton proton chain start?
10,000,000 K
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What temperature does the CNO chain start?
16,000,000
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roche lobe
The volume of space a star controls gravitationally within a binary system
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Roche surface
The dumbbell-shaped surface that encloses the Roche lobes around a close binary star
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Lagrangian points
Points of gravitational stability in the orbital plane of a binary star system or of a planet and its moon.
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inner Langrangian point
The point of gravitational equilibrium between two orbiting stars through which matter flows from one star to the other
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