A Search for Extrasolar Planets from the South Pole

该项目将在南极运行一个小型光学望远镜，通过使用电荷耦合装置光度计连续跟踪银河系南部恒星场，搜索行星经过其母星时发生的周期性变暗，从而搜索和描述太阳系外行星的特征。最近发现了许多接近的巨型系外行星，这扩大了我们对其他行星系统的了解，并证明了这些系统与太阳系有多么不同。然而，他们的发现提出了关于这些行星对宜居行星存在的影响的重要问题。到目前为止，只观察到一颗太阳系外行星HD 209458b凌日了一颗母星。该项目有可能将观测到凌日的太阳系外行星的数量增加十倍。南极是探测这类行星的绝佳地点，因为漫长的冬夜可以最有效地探测到随机相变的凌日。此外，极地恒星场的恒定高度避免了大气日大消光变化，从而实现了更高的光度精度和搜索较小的行星。具体地说，该项目将在南极建立一个自动寻找行星的光度计，用于南极的两个南半球冬季。根据对附近太阳型恒星的行星系统的统计，应该可以探测到大约10到15颗太阳系外行星。也有可能找到以前无法探测到的质量较低的行星。将凌日结果(给出行星的大小)和多普勒速度测量(给出行星质量)结合起来，就可以确定行星的密度，从而表明这颗行星是像木星一样的气态巨星，像天王星这样的冰巨星，还是像地球一样的岩石行星。这些数据将提供对行星结构和形成的理论模型至关重要的基本观测信息。

This project will operate 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, 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 to transit a parent star. This project has the potential for a tenfold increase in the number of extrasolar planets for which transits are observed. The South Pole is an excellent location to detect such planets because of the long winter night, during which randomly-phased transits can most efficiently be detected. Also, the constant altitude of a stellar field at the pole avoids large daily atmospheric extinction variations allowing for higher photometric precision and a search for smaller planets.Specifically, the project will establish an automated planet-finding photometer at the South Pole for two austral winter seasons. Based on the statistics of planetary systems of nearby solar-type stars, about ten to fifteen extrasolar planets should be detected. There is also a 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 determination of the planetary density, thus indicating whether the planet is a gas giant like Jupiter, an ice giant like Uranus, or a rocky planet like the Earth. These data will provide basic observational information that is vital to theoretical models of planetary structure and formation.