Quiz 8 Learning Goals and Supplemental Resources
[Fix, Astronomy: Journey to the Cosmic Frontier, 4/e, Chapters 7 (partial), 16 (partial)]
[Reading guide (*.pdf)]
[CPS inquiry questions (*.pdf)]
[CPS review questions (*.pdf)]
- Understand how parallax is used to determine distances to (nearby) stars, and how the Doppler effect is used to determine the radial motion of stars with respect to the Earth.
- Stellar Motion and Distance handout (*.pdf)
Compare how the wavelengths of light are affected by whether the source of light is moving towards or away from an observer. Also understand the relationship between the parallax shift of a star, with respect to its distance away from the Sun.
- Websites:
- Doppler Shift Interactive (*.swf)
Use this simulation to reproduce the scrunching or spacing apart of wavefronts emitted from a source moving towards/away from an observer, cf. Fig. 6.6, p. 106 from Fix, Astronomy: Journey to the Cosmic Frontier, 4/e (McGraw-Hill Publishers).
- Diane Lane demonstrating stellar parallax (*.gif animation)
Understand the analogy between her left/right eyes, nose, wine bottle, and house with the Earth, Sun, nearby star, and distant stars. (Under the Tuscan Sun, Touchstone Pictures movie, 2003.)
- Stellar Parallax demonstration (java applet)
Compare how different parallax shift angles are produced by stars at different distances.
- Parallax/Solar System modeler (java applet)
Interactive 3-D simulation of how parallax angles are determined.
- Understand how the absolute magnitude ("script M") or luminosity L of a star can be determined (qualitatively) from its apparent magnitude ("small m") and distance from the Earth, relative to a standard 10 parsecs.
- In-class activity 17, Apparent/Absolute Magnitudes, and Star Distances (*.pdf)
Relate apparent and absolute magnitudes as measures of brightnesses, and the actual distance and the standard 10 parsec distances of stars.
- Understand how the peak wavelength (and color) and intensity of blackbody radiation (continuous spectra) are described by Wien's law and by the Stefan-Boltzmann law.
- In-class activity 18, Blackbody Radiation Laws (*.pdf)
Discuss how Wien's law and the Stefan-Boltzmann law are used to compare the relative temperatures and sizes of stars, given their blackbody spectra.
- Websites:
- Cooking Pot as Blackbody (java applet)
Simulation of the different glowing colors emitted by a blackbody, as a function of temperature
- What Color is a Blackbody? (*.html)
(For reference.) Table of hexadecimal RGB pixel values for blackbody colors of different temperatures.
- Blackbody Spectrum Applet (java applet)
Note how the characteristic "blunt-front, long-tail" hump of a blackbody spectrum changes with respect to temperature, as it obeys both Wien's and the Stefan-Boltzmann law.
- Understand how absorption/emission spectra are caused by electrons jumping up/down to higher/lower energy orbits and are used to "fingerprint" the type of atoms, and how continouous/absorption/emission spectra are related to the size/density of a light source (Kirchhoff's laws).
- Bohr Model of an Atom handout (*.pdf)
Simplified model of how an electron is moves around the nucleus of an atom in only certain allowed orbitals. Also understand how absorbing a photon with the correct amount of energy allows an electron to move "up in energy" to an outer orbital, or how an electron may emit a photon with an certain amount of energy to move "down in energy" to an inner orbital.
- The Bohr Atom Interactive (*.swf)
"Toy" model of a hydrogen atom (one electron, one proton). Understand how "jumping" to any higher orbital requires a specific type of photon to be observed, and how "jumping" to any lower orbital requires a specific type of photon to be emitted (McGraw-Hill Publishers).
- Fig. 16.6 from Fix, Astronomy, Journey to the Cosmic Frontier, 4/e (*.jpg)
Three principal types of spectra. Note that light rays mysteriously seem to pass straight through the prisms, and that the glowing object at left is not a star, but represents a hot solid object (how is this so?).
- Website:
- Understand how the Stefan-Boltzmann law can be used to relate the luminosities, temperatures and sizes of stars from an H-R diagram.
- In-class activity 19, OBAFGKM Poetry Slam (*.pdf)
A creative self-expression assignment to be presented in-class, such that you can memorize the order of spectral classification types. A tongue-in-cheek example from a previous semester is here.
- H-R diagram handout (*.pdf)
This chart is provided in Midterm 3, and thus need not be memorized. Understand how and why stars group in the four main categories (main sequence, white dwarfs, giants and supergiants) given a temperature and a brightness parameter, using the Stefan-Boltzmann law.
- Websites:
- Sagittarius Star Cloud (*.jpg)
Compare the colors of these stars, and understand how Wien's law can be used to determine their surface temperatures (The Hubble Heritage Project).
- Size Comparison of Several Stars (*.gif)
Artist's rendering of the different sizes and colors of typical stars (NASA Goddard Space Flight Center).
- Blackbody Radiation Interactive (*.swf)
Understand how the temperature and size of a star affects its luminosity (i.e., absolute magnitude), via the Stefan-Boltzmann law. Note that the vertical intensity scale of the blackbody spectrum is arbitrarily set (McGraw-Hill Publishers).
- Starry Night file:
- H-R diagram of visible San Luis Obispo, CA stars (*.snf)
If the H-R diagram window does not show up, open it by going under the Window > H-R Diagram pull-down menu. Scan around the sky and see how many main sequence stars, supergiants, and giants are plotted. (White dwarfs and red dwarfs are too dim to be visible and thus not placed on this diagram, but are actually the most numerous type of stars.)
Archived Quizzes and Exams
Please read the disclaimer regarding archived quizzes and exams before downloading.
To view the interactive Starry Night (*.snf) files used in lecture, first download them to your hard drive using Internet Explorer ("download link to disk"), and then open them using the Starry Night Pro program (available from the CD-ROM enclosed with Astronomy: Journey to the Cosmic Frontier, 4/e, or a demo Starry Night Backyard version (available for a free two-week trial period for either Windows or Mac OS systems).
|
