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PPhysicsMathematicsS5 to S6Astronomy
Astronomy lab: find a planet around another star
Astronomers have found thousands of planets around other stars by watching them dim slightly. Read real-style light curves and discover your own planets.
LevelS5 to S6 (and A Level, IB)
TimeAbout 40 min
You useGraphs, square roots, Kepler’s law
PriceFree: no account
🎯 Aim
To use the transit method to find planets around other stars, and to calculate their radius and orbit from a light curve.
You will learn to
- Read the depth and period of transits from a light curve.
- Calculate planet radius from the depth.
- Use Kepler’s third law to find the orbit radius.
- Explain why small planets are hard to detect.
🧭 What to do
- Look at the light curve of Star 1: find the dips.
- Choose Zoom on the first dip and read its depth.
- Set Dip depth you read and Time between dips you read: what kind of planet is it?
- Do the same for Star 2 and Star 3.
- Answer the questions with the class data.
- Write your conclusion and download your lab report.
📋 The data
Times and lowest brightness of the dips of star 1 over 30 days.
🧠 Investigate: answer from the data
Type your answer and tap Check. Use 💡 Hint first; open the method only when you are stuck.
➕ Get more from this experiment
📝 Free
Print the worksheet (button above), download the data, and save your report. Teachers can project this page in class.
📦 Premium Lab Pack
1 000 RWF
- Worksheet: light curves to analyse by hand
- Kepler’s laws and planets problems
- Teacher guide and answer key
- Exam-style questions with marking scheme
👩🏫 For teachers
Use it as a practical when apparatus is missing, as homework, or as a project. Free lesson plans help you plan, teach and assess.
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