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Chapter 5: 5-8 Homework

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Scholars Online Astronomy - Chapter 5: 5-8: Stellar Spectra


Reading Preparation

Reading: Astronomy, Chapter 5: Sections 5-8 Stellar Spectra, Composition, and the Doppler shift

Study Notes: notes on your assigned reading from the text

Key Formulae to Know

  • Planck's law E   =   hc λ   =   h ν

    h = 6.625 * 10-34 Joule-seconds = 4.135 * 10-15 eV-seconds

  • Bohr's law 1 λ   =   R   ( 1 n i 2   1 n o 2 )  

    R = 1.097 * 107 m-1

  • Doppler shift λ   λ 0   λ 0   =   Δ λ λ 0   =   v c

Web Lecture

Read the following weblecture before chat: Light and how it tells us what's out there (Part 2)

Study Activity

  • Stellarium: Examine the Virgo Cluster. The Virgo Cluster is a group of more than 2000 galaxies extending across 9 million light-years, located about 50 million LY from Earth. Use your program to examine galaxies in the cluster more closely. Center your view on Messier 87 and zoom in until you can see the string of galaxies above M87 and galaxies to the left and right. You should check out at least three of the following (look these up in Wikipedia as well to get detailed pictures).
    • Messier 87
    • Messier 49
    • Messier 81
    • Messier 84 (NGC 4374)
    • Messier 86 (NGC 4406)
    • NGC 4438
    • NGC 4461

    Are all of the galaxies the same color throughout? Do all galaxies contain stars of the same surface temperature? Locate several spiral galaxies. What are the dominant colors of the inner and outer regions of these galaxies? What can you conclude about the surface temperatures of the brightest stars in the inner regions compared to the surface temperatures of those in the outer spiral?

UNL Tools Exercises

  • Interactives:
    • Do at least two of the five interactive exercises on the Doppler shift.
  • ClassAction:
    • Review any Light and Spectra Module concepts that still confuse you.
  • NAAP Labs:
    • Work through the Hydrogen Energy Levels materials, then use the Hydrogen Atom simulator to explore how electron transitions absorb or emit photons of specific energy amounts.

Optional Websites: Astronomy Answers (On Light) has a number of questions (and answers) commonly asked about light by astronomy students.

Chat Preparation Activities

Chapter Quiz

Lab Work

Read through the lab for this week; bring questions to chat on any aspect of the lab, whether you intend not perform it or not. If you decide to perform the lab, be sure to submit your report by the posted due date.