This exercise is the same as the Interactive exercise #2 that is located in Module 2 Lecture D.

• Launch the Periodic Table
  
  

  Click on an element to bring up its spectra in the two vertical windows. Mouse over the features to read off the wavelengths of those features Note that may more features are visible in Terrestrial Lab spectroscopy than in an actual stellar atmosphere. However, the wavelengths of the features are exactly the same.

  
  
  

• Launch the Absorption Line Simulator
  
  However, this simulator will most likely fail to launch so in that case refer to the images below. For elements AX and BX we have recorded the wavelengths of 4 absorption lines in the spectra of the stars.
  
  AX:
  
  
  
  BX:
  
  In the above figures, the left cell is a screen shot for element AX or BX showing the 4 spectral lines (wavelengths omitted); in the right is a table which tabulates those wavelengths that you would need to match up with the periodic table of elements.
  
  One hint: Elements AX and BX all have atomic numbers less than 20.
  
  In the template you should list the wavelengths of the spectral lines that you determined in the periodic table of elements as close matches to the wavelengths for the given lines in the two tables corresponding to AX and BX.
  
  When you find an element with 4 closely matching lines, then report that element in the provided template.
  
  
  
  Question 2:
  
  Refer to the picture to the right of A, B and C to answer the posed question.
  
  

  A) List all the possible values of photon energies that this atom can "emit" on its return to the ground state.

  B) An incoming photon has energy = 9 units. What will happen to the photon and the electron?

  C) An incoming photon has energy = 5 units. What will happen to the photon and the electron?

  
  
  
  
  Question 3. This refers to the material in Module 3 Lecture A as related to the determination of stellar parallax by Tycho.

  Open the simulation. (FLASH based)

  At the bottom is your detector, in this case 3 independent pixels. The eye above reflects the orbit of the Earth around the Sun. The angle is the parallax angle. In order for a parallax to be detected, the Star has to move at least one independent pixel. In this default case, there is no detection - the star does not change pixels (the star is too far away and/or the resolution of the detector is too imprecise).

  The course grid simulates measurements from the ground through our atmosphere.

  The Fine Grid refers to measurements made from space.

  Separation refers to distance from the Earth to the star; smaller values are larger distances.

  a) With the course grid checked (i.e. 3 pixels), what is the required minimum separation (i.e. the distance to the star) to produce a detection. Increment the seperation by clicking on the arrows?

  b) Leaving the separation at that minimum value, click on Fine Grid. How many pixels (e.g. resolution elements) of movement is there in this case?

  c) Explain why space based observations offer a much better way of detecting stellar parallax than can be done from the ground.

  Question 4

  Here we use the Spectra Simulator in the manner outlined in the material of lecture 2E.
  
  You are to make the relevant measurements of the Hydrogen line at 4860 angstroms and the Calcium doublet line at 3935 and 3930 angstroms for the three different spectral types, F4-7, G8 and K5 and report the respective values in the template.