Over the past few hundred years, astronomers have discovered thousands of stars whose brightness goes up and down over time. These are known as variable stars. But what causes this to happen? And how can we measure the changes in brightness?
In this activity, you will create a light-curve for a variable star called W UMa. A light-curve is a graph that shows how the brightness of an object changes over time. You will measure the brightness of W UMa and two comparison stars and input the data into an Excel spreadsheet. The required calculations are undertaken for you, with the results automatically plotted on to a light-curve. You will then compare this with known examples of classify W UMa’s variable type.
You can choose whether to analyse some of the data (Short Activity) or all of it (Full Activity). Each option has the same outcome.
By the end of this resource you will:
- Know how to measure the brightness of a star using a technique called photometry
- Have used astronomical software to take accurate measurements
- Have recorded measurements accurately
- Have created a light-curve for a known variable star
- Understand how to classify a variable star from its light-curve and period
To complete this resource you will need:
- Access to the internet
- A computer browser to access the AstroLab Stellar software
- A copy of the worksheet
- A copy of the results Excel spreadsheet
- The ‘W UMa – Data Set 3’ (Short Activity) or all the data sets (Full Activity)
- A copy of the answers
