Finding Exoplanets (a simulation)

INTRODUCTION

Since the early 1990's the existence of more than 100 extrasolar planets or exoplanets, i.e., planets orbiting stars other than our Sun, has been documented. Most of these have been large gaseous planets with masses just less than to many times more than Jupiter's mass. However, the Kepler Mission has a photometer designed to collect data for many years on the light output from a star. This data can then be analyzed for indications of the existence of smaller, Earth-size, exoplanets. The launch of the Kepler Mission is planned for 2006.

There are three primary methods that can be used by astronomers to locate exoplanets.

• Photometry - the measurement and analysis of the amount of light coming from a celestial object (in this case a star). A periodic drop in light intensity may infer the presence of an unseen planet transiting across the face of the star obstructing some of the light output.
• Astrometry - the measurement and analysis of the position of a star against the backdrop of surrounding stars. A star demonstrating a regular oscillation in position may have an unseen planet orbiting it causing this "wobble" of the center of mass of the star-planet system.
• Spectroscopy - the measurement and analysis of the spectrum of a star. If the absorption lines in the spectrum show a periodic motion from being red-shifted to blue-shifted to red-shifted, etc., this may indicate that a planet is orbiting the star causing it to very slightly shift position as the star and planet orbit about their mutual center of mass.

The simulation provided here uses photometry (or measuring the decrease of the light coming from a star as a planet transits across its face) to search for potentially habitable exoplanets.

Note Before Executing The Exoplanet Simulation Below

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FINDING EXOPLANETS - A SIMULATION

• Exoplanet Simulation
• Exoplanet Exercise

RESOURCES

Web Sites

• Kepler Mission ( http://www.kepler.arc.nasa.gov/ )
• Extrasolar Planets Encyclopedia ( http://cfa-www.harvard.edu/planets/ )
• Planet Quest - news and info of missions looking for exoplanets
  ( http://planetquest.jpl.nasa.gov/ )
• Search for Extrasolar Planets - a tutorial (somewhat dated but still good)
  ( http://www.public.asu.edu/~sciref/exoplnt.htm )