Astronomy 490                                  Homework #3                                         Spring 2007



Due date:   Monday, Feb 19 at start of class



Journal paper:  

   Weaver et al. 2006, The Discovery of Two New Satellites of Pluto, Nature, 439, 943




Additional reference:  Chiang et al. 2007, A Brief History of Trans-Neptunian Space

                                       in Protostars and Planets V, p. 895 (astro-ph/0601654)



1.  Read the Weaver paper carefully, more than once.  Then, in one type-written page,

     write an essay, in your own words, explaining the following:


      (i)  What are the arguments that these two objects are really related to Pluto?


      (ii)  What are the arguments that these two objects, with only two measurements each,

              really are in circular orbits in the same plane as the Pluto/Charon orbit?


     For this part of the essay, assume that your reader is a fellow physics student who has

      never taken an astronomy course.


     Finally, write a few sentences about whether you find the arguments in this paper

     convincing.  If not, why not?  If so, what convinced you?



2.   Read sections 1 and 2 (i.e., the first 5 pages) of the Chiang et al. review paper

      carefully, taking notes as you read as an aid to comprehension and memory.  As with

      any scientific article, pay particular attention to the figures. Note that Figure 1 is  

      found on p. 17 of the article.  Skim the rest of the article.  Turn in your notes on

      sections 1 and 2 with the rest of your homework.