Marois Christian, Macintosh Bruce, Barman Travis, Zuckerman B, Song Inseok, Patience Jennifer, Lafrenière David, Doyon René
National Research Council Canada, Herzberg Institute of Astrophysics, 5071 West Saanich Road, Victoria, BC V9E 2E7, Canada.
Science. 2008 Nov 28;322(5906):1348-52. doi: 10.1126/science.1166585. Epub 2008 Nov 13.
Direct imaging of exoplanetary systems is a powerful technique that can reveal Jupiter-like planets in wide orbits, can enable detailed characterization of planetary atmospheres, and is a key step toward imaging Earth-like planets. Imaging detections are challenging because of the combined effect of small angular separation and large luminosity contrast between a planet and its host star. High-contrast observations with the Keck and Gemini telescopes have revealed three planets orbiting the star HR 8799, with projected separations of 24, 38, and 68 astronomical units. Multi-epoch data show counter clockwise orbital motion for all three imaged planets. The low luminosity of the companions and the estimated age of the system imply planetary masses between 5 and 13 times that of Jupiter. This system resembles a scaled-up version of the outer portion of our solar system.
系外行星系统的直接成像技术十分强大，它能够发现处于宽轨道上类似木星的行星，还能实现对行星大气的详细特征描述，并且是朝着成像类地行星迈出的关键一步。成像探测颇具挑战性，这是由于行星与其主恒星之间小角距和大光度对比度的综合影响。利用凯克望远镜和双子望远镜进行的高对比度观测发现了三颗围绕恒星HR 8799运行的行星，其预计间距分别为24、38和68天文单位。多历元数据显示，所有三颗已成像行星都在做逆时针轨道运动。伴星的低光度以及该系统的估计年龄意味着行星质量在木星质量的5至13倍之间。这个系统类似于我们太阳系外部放大版。
