Investigating Planets
Going Further

Extrasolar Planetary Systems

Introduction: For centuries, the only known planets were those circling our own Sun. It was not even known if planets were rare or common in the universe. In the last decade or so, however, hundreds of planets have been discovered around other stars. Several stars are known to have more than one planet. How do these new planetary systems compare with our own? Are the planets near to their parent star or far away? Are they all the same size? Do they all orbit in the same plane like the planets in our system, or are the orbits all askew? Take a closer look at the data we have on these new planetary systems and explore these questions yourself.

Directions:
Go to The Extrasolar Planets Encyclopedia at: http://exoplanet.eu/, select the Interactive Catalog, and then All Candidates detected. That will bring up the latest list of known extrasolar planets. The table includes information about the star (click on the planet's name), and estimates of the masses of the planets and parameters describing their orbits – enough information to make your own drawing or model of the system. Select a few representative systems and use the techniques developed in the module to create your own model of each system, either using clay or making a scale drawing . For systems including more than one planet, see if you can think of a way to show how the orbits are oriented to each other. Compare with our own planetary system.

Your Report:
1) Prepare a display showing your drawings or physical models. Provide a written description of each and a comparison of the modeled systems with our own. Are there any similarities? How are they different? Can you estimate the surface temperatures of the extrasolar planets?

2) Participate in a search for an extrasolar planet! If you have access to a good telescope, you can join one of the teams actively searching for more extrasolar planets. One project is PlanetQuest at: http://www.planetquest.org/. Visit their site and look into the possibilities of helping measure the transit of an extrasolar planet across its primary star's disk.