Exam 2: Stars (take home test)
Name ___________________________________

Star Name _______________________________		 Score _______________

Date: ________________
   

Introduction

 Each of you has your very own star. By the end of this exam, you be an Astronomy 101U/V expert on that one star. I expect your work to be complete, accurate, and above all, representative of your best effort. Answer all questions as explicitly and specifically as possible. Supply all information in the spaces provided on these sheets. Please make sure I can easily read your writing; otherwise, I will assume you really didn't want me to.

In some cases, you will have to estimate some qualities or quantities for your star. (For example, you cannot find any definite information about the evolutionary stage of your star. Would a star of exact or similar spectral type and luminosity class do as a reference?) As is the case for the labs this quarter, just make sure that you spell out the logic you used. Original and/or sound reasoning is just as important as getting the "right" answer. You may find conflicting values for your star in the sources you use. Please reference your source in your work.

Important Links, References, and Equations

Links

Constellations and an alphabetical star list by Chris Dolan.
Portraits of Stars and Their Constellations, by Dr. James B. Kaler.
More Star names and constellations, this time from Sky Eye.
Star Maps for Hawai'i by month -- look for "Bishop Museum Sky Maps" link. Also contains detailed information and maps on the constellations -- look for "Constellations Listing."
A straight-forward listing of stars from Your Sky that includes Bayer Designation ("Identity") and star fields.

References

Equations

The book has figures that will tell you the approximate numbers to use:

Questions

  1. Identifying Your Star

    (5 pts) Find a star map of your constellation and reproduce that map here. Include at least 6 stars, include the outline of the constellation and identify which star is your star.
     

  2. Stellar Parameters(7 pts)

    Star NameBayer
    Designation    		 Spectral
    Type    		Luminosity
    Class    		 Apparent
    Magnitude    		Absolute
    Magnitude    		 Distance
    (Parsecs)
            


  3. Observing your Star

    1. (2 pts) You have been given a whole week to observe your star using the 4-meter telescope on the big island of Hawai'i. Which month would be the best one to observe your star; that is, which month has the constellation rising in the East at approximately 8 - 9 pm?



    2. (2 pts) Calculate the wavelength (or use the appropriate figure in the book) at which your star radiates most of its energy (peak wavelength of the star's thermal radiation). Show all work or reference the figure you used.




    3. (4 pts) Consider the wavelengths at which your star radiates most of its energy. Should you apply for time on the Hubble Space Telescope or will a ground-based telescope be sufficient? Explain your answer.






  4. The Evolution of Your Star

    1. (4 pts)Reproduced here is Fig. 14.15 of your text. Fill in the life track of a 1 solar-mass star from main sequence to red-giant stage. Do the same for a 3 solar-mass star and a 6 solar-mass star assuming the evolution off of the main sequence follows their birth to the main sequence (Fig. 14.8). Using this chart (or another appropriate figure), and the spectral type and luminosity of your star, find an approximate mass for your star.
      (2 pts)Mass:
      (2 pts)Uncertainty:


    2. Based on the mass of your star and where your star is on the HR Diagram:
      • (2 pts)What is probably happening in its core?


      • (2 pts)How is the rest of the star being supported?


      • (2 pts) Approximately how long did (will) your star spend on the main sequence? (Show all work or reference the figure used.)



    3. Peer into your crystal ball (oops, astrophysicists don't have crystal balls -- substitute mathematical model):
      • (2 pts)What is probably the next stage for your star?


      • (2 pts)How will your star die?



    4. (2 pts) Name one thing that probably characterized the birth of your star.




    Bonus Points

    (5 pts)Find something astrophysically notable about your star. State it here and then explain it to your non-science roommate.



















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