Asteroid Light Curves - Introduction

In the Hands-On Universe curriculum there are activities in which you measure the brightness of certain objects in a series of images. When you plot this data, you find that the brightness changes and that astronomers refer to the resulting graph as a light curve. You can do this for supernovae and Cepheid variable stars in HOU units. These graphs help astronomers gain a better understanding of the behavior of those objects. At some point in time during the study of Solar system objects astronomers took a closer look at asteroids by imaging them many, many times day after day. When the images were analyzed and the brightness plotted versus time, guess what they found? The graphs revealed periodic changes in the brightness of many asteroids. How can that be? How can an object that does not emit its own light vary in brightness?

If you are uncertain of why this could be the case, take a few moments to discuss it with a colleague or team member.

If you are interested in working with a series of images to investigate this area of asteroid study, please follow this link.