Card Set Information

2010-04-17 20:05:03

Test 2 vocab and concepts
Show Answers:

  1. Coulomb force
    The electrostatic force of repulsion or attraction between charged bodies
  2. binding energy
    The energy needed to pull an electron away from its atom
  3. quantum mechanics
    The study of the behavior f atoms and atomic particles
  4. Permitted Orbit
    One of the energy levels in an atom that an electron may occupy
  5. Black body radiation
    Radiation emitted by a hypothetical perfect radiator
  6. Wavelength of maximum intensity
    The wavelength at which a perfect radiator emits the maximum amount of energy; depends only on the objects temperature.
  7. Joule
    A unit of energy equivalent to a force of 1 newton acting over a distance of 1 meter
  8. continuous spectrum
    A spectrum in which there are no absorption or emission lines
  9. absorption spectrum
    A spectrum that contains absorption lines caused by photons being absorbed by atoms or molecules
  10. absorption line
    a dark line in a spectrum; is produced by teh absence of photons absorbed by atoms or molecules
  11. emission spectrum
    a spectrum containing emission lines
  12. emission line
    a bright line in a spectrum caused by the emission of photons from atoms
  13. Kirchhoff's laws
    A set of laws that describe the absorption and emission of light by matter
  14. transition
    the movement of an electron from one atomic energy level to another
  15. Lyman series
    Spectral lines in the ultraviolet spectrum of hydrogen produced by transitions whose lowest energy level is the ground state
  16. Balmer series
    A series of spectral lines produced by hydrogen in the near ultraviolet and visible parts of the spectrum
  17. Paschen series
    Spectral lines in the infrared spectrum of hydrogen produced by transitions whose lowest energy level is the third
  18. radial velocity
    A component of an object's velocity directed away from or toward Earth
  19. isotope
    An atom that has the same number of protons but a different number of neutrons
  20. Ion
    An atom that has the same number of protons but a different number of electrons
  21. 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
  22. 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
  23. 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.
  24. 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.
  25. Filaments
    Solar prominences seen from above silhouetted against the bright photosphere
  26. spicules
    Small, flamelike projections in the chromosphere of the sun
  27. magnetic carpet
    The network of small magnetic loops that covers the solar surface
  28. Zeeman effect
    The splitting of spectral lines into multiple components when the atoms are in a magnetic field.
  29. differential rotation
    The rotation of a body in which different parts of the body have different periods of rotation
  30. Prominence
    A loping eruption on the solar surface of ionized gas trapped in a magnetic field.
  31. reconnections
    On the sun, the merging of magnetic fields to release energy in the form of flares.
  32. Coronal mass ejections
    matter ejected from the sun's corona in powerful surges guided by magnetic fields
  33. 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
  34. What causes the dynamo effect?
    A magnetic field is produced when a rapidly rotating conductor is stirred by convection
  35. 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
  36. 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.
  37. 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.
  38. 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
  39. Flux
    A measure of the flow of energy out of a surface, usually applied to light
  40. Light curve
    A graph of brightness vs. time
  41. Parsec
    The distance to a star whose parallax is one second of arc.
  42. Kepler's first law
    The orbits of the planets are ellipses that are very nearly circles
  43. Keplers second law
    An imaginary line drawn from the planet to the sun always sweeps over equal areas in equal intervals of time
  44. Keplers third law
    A planet's orbital period is related to its average distance from the sun
  45. Newtons first law of motion
    A body continues at rest or in uniform motion in a straight line unless acted upon by some force.
  46. 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
  47. 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
  48. Spectral classes from hottest to coldest
    O, B, A, F, G, K, M
  49. Luminosity Class Ia
    Bright Supergiant
  50. Luminosity Class Ib
  51. Luminosity Class II
    Bright giant
  52. Luminosity Class III
  53. Luminosity Class IV
  54. Luminosity Class V
    Main-Sequence star
  55. What does a light curve measure?
    brightness vs. time
  56. What is the most common spectral class of main-sequence stars?
    Class M
  57. Spectral class O
    40,000 K Weak Balmer lines
  58. Spectral Class B
    20,000 K Medium Balmer Lines
  59. Spectral Class A
    10,000 K Strong Balmer lines
  60. Spectral Class F
    7500 K Medium Balmer lines
  61. Spectral class G
    5500 K Weak Balmer lines
  62. Spectral Class K
    4500 K Very weak Balmer lines
  63. Spectral Class M
    3000 K Very very weak balmer lines Only stars with Titanium Oxide
  64. 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."
  65. 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.
  66. 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.
  67. 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.
  68. 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
  69. 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.
  70. 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.
  71. First law of Stellar Structure
    Conservation of mass
    Total mass equals the sum of shell masses
  72. Second Law of Stellar Structure
    Conservation of Energy
    Total luminosity equals the sum of energy generated in each shell
  73. Third Law of Stellar Structure
    Hydrostatic equilibrium
    The weight on each layer is balanced by the pressure in that layer
  74. Fourth Law of Stellar Structure
    Energy Transport
    Energy moves from hot to cool regions by conduction, radiation, or convection
  75. Herbig Haro objects
    Formed when powerful jets from a newborn star strike the interstellar medium.
  76. T-tauri stars
    Stars that fluctuate in brightness and appear to be newborn stars just blowing away their dust cocoons
  77. Reflection nebulae appear to be what color?
  78. Stars that contract the slowest to land on the zero-age main sequence line on the H-R diagram are the _____ massive
  79. To begin to collapse into stars, an interstellar cloud must be?
    Cold and dense
  80. What two characteristics are balanced in hydrostatic equilibrium?
    weight and pressure
  81. When a star begins its stable life, it begins on the
    Zero age main sequence
  82. 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.
  83. 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
  84. What would happen if the sun stopped generating energy?
    With no pressure to push outward against gravity, it would collapse.
  85. 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
  86. 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.
  87. 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
  88. 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
  89. 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.
  90. What temperature does the proton proton chain start?
    10,000,000 K
  91. What temperature does the CNO chain start?
  92. roche lobe
    The volume of space a star controls gravitationally within a binary system
  93. Roche surface
    The dumbbell-shaped surface that encloses the Roche lobes around a close binary star
  94. Lagrangian points
    Points of gravitational stability in the orbital plane of a binary star system or of a planet and its moon.
  95. inner Langrangian point
    The point of gravitational equilibrium between two orbiting stars through which matter flows from one star to the other