Research Objectives:
This group operates a small optical telescope at the South Pole to search for and characterize extrasolar planets by continuously following a southern galactic star field with a charge-coupled device photometer and searching for the periodic dimming that occurs as a planet transits its parent star.
The recent discovery of many close-in giant exoplanets has expanded our knowledge of other planetary systems and has demonstrated how different such systems can be from the solar system. However, their discovery poses important questions about the effects of such planets on the presence of habitable planets. To date only one extrasolar planet—HD 209458b—has been observed transiting a parent star. This project has the potential for a 10-fold increase in observations of such transits.
The South Pole is an prime location for finding extrasolar planets by observing transits for several reasons: The long winter night allows researchers to observe stars continuously for several months. At lower latitudes, daylight hours prevents observations of 1/2 to 2/3 of all transits. During the polar night, the stars never rise or set thus minimizing the brightness change associated with the rising and setting of lower latitudes. The cold stable atmosphere also minimizes the changes in brightness that occur as the stars twinkle (scintillation noise). Both of these noise sources hinder precise brightness measurements.
Researchers will establish and operate an automated planet-finding photometer at the South Pole for two austral winters. The statistics of planetary systems of nearby solar-type stars would indicate that about 10 to 15 extrasolar planets should be detected. There is also the possibility of finding lower mass planets that have not previously been detectable. Combining the transit results (which give the size of the planet) with Doppler velocity measurements (which give the planetary mass) will allow the planetary density to be determined, thus indicating whether the planet is a gas giant like Jupiter, an ice giant like Uranus, or a rocky planet like Earth.
