Exercises

In this lab, we will mostly be looking at images of the Sun that were taken with a H-alpha filter.

  1. What is the H-alpha spectral line, and why do we use it to observe the Sun?
     
  2. In the table in your packet, there are five features that are found on the Sun. Research each feature. List how each feature would look on an H-alpha image and filling the ‘How to Identify’ column in the table. Then, list in the second column what region the feature is located in (e.g., photosphere, corona) and what physics is driving the formation of the feature.

    You will now examine two images of the sun, one in white light and the other in H-Alpha light. Using the table you complied in Question 1, identify the visible features in each image.  The online versions of the images in your packet are here: H-alpha , white light.
     
  3. Using the two images of the Sun and the table you compiled in Question 2, identify the features that are present in each image. (Note: Not all features are visible in both images.)
     
  4. How are solar prominances and solar filaments similar?  How are the different?

Background

Sun full

The Sun is mostly 73% hydrogen, 25% helium, and the remaining 2% is trace amounts of heavier elements like oxygen, carbon, nitrogen, etc. Most of this material is a plasma, which is one of the four fundamental states of matter. A plasma is created by super heating gas, or subjecting gas to magnetic fields, such that the electrons and protons are no longer bound to an atom or molecule. Because electrons and protons are charge particles, they are subject to electromagnetic forces. In fact, it is a good approximation to think of the plasma carrying the magnetic field with it or that the magnetic field is ‘frozen’ into the plasma.

Electric and magnetic fields are important in the convection zone of the Sun, where the plasma is being churned as it cycles towards the photosphere. Since the Sun is rotating, the plasma will also rotate, causing the magnetic fields to wrap and twist on the surface of the Sun. Many features we can observe on the photosphere, chromosphere, and the corona of the Sun are caused by magnetic fields. These features include sunspots, plage, prominence, filament, and granulation.