At the bottom of this entry, I give the Weekly Pondering 5 assignment, for those of you in ASTR 1/2. Any text that you need to read is on Blackboard or linked to here.

We have seen that, since the Sun is by far the closest star to Earth and is a mostly typical star, we can learn about distant stars by studying our Sun. To observe distant stars directly, however, we must look at stars’ light emissions. The light that stars emit is referred to as the stars’ spectra. We learned about spectra from a previous lecture, when we discussed atoms and light.

In the video, Kimberly Arcand discusses how she and her team measure and study dead stars. Notice that they observe stars in various parts of the electromagnetic spectrum, which gives astronomers a much clearer and fuller picture than keeping just to the visible part of the spectrum. She gives the example of her favorite astronomical object, Cassiopeia A. Do a search for images of this object, and find an image that contains information from the infrared, visible, and X-ray part of the spectrum. Use only proper sources, such as the Jet Propulsion Laboratory, the European Space Agency, etc., and be prepared to mention your source during the WP office hour. Do a bit more research on Cassiopeia A, to determine (a) what kind of object it is, and (b) what the central star is. Also, try to think of at least one question you have about this object that seems mysterious to you. In a paragraph or two, write your answers to these questions, describe your question(s), and include the link (and its source) to the image of Cassiopeia A.