A planetary system as the origin of structure in Fomalhaut's dust belt
A planetary system as the origin of structure in Fomalhaut's dust belt
复制标题
作为北落师门尘埃带结构起源的行星系统
作者：
P. Kalas;J. Graham;M. Clampin
太阳和超过15%的邻近恒星被尘埃盘包围，这些尘埃盘必须由小行星和彗星碰撞补充，否则尘埃将在<107年的时间尺度上耗尽（参考文献1）。理论研究表明，尘埃盘的结构可以被行星的引力影响所改变，但观测证据是不完整的，至少部分是因为尘埃盘的热红外辐射图的线性分辨率很低（最好的情况下为35 Au）。光学图像提供了更高的分辨率，但最接近的例子（Au Mic和β Pic）是边缘上的，阻止了直接测量方位角和径向盘结构，这是拟合行星摄动理论模型所必需的。在这里，我们报告的光学光反射的尘埃颗粒轨道北落师门（HD 216956）的检测。该系统从边缘倾斜24°，能够测量整个圆周周围的盘结构，线性分辨率为0.5 Au。尘埃分布在一个25 Au宽的带中，在133 Au的径向距离处有一个非常尖锐的内边缘，我们测量到带的几何中心和北落师门之间的偏移量为15 Au。总之，尖锐的内边缘和偏移表明北落师门轨道上存在行星质量的物体。
The Sun and >15 per cent of nearby stars are surrounded by dusty disks that must be collisionally replenished by asteroids and comets, as the dust would otherwise be depleted on timescales <107 years (ref. 1). Theoretical studies show that the structure of a dusty disk can be modified by the gravitational influence of planets, but the observational evidence is incomplete, at least in part because maps of the thermal infrared emission from the disks have low linear resolution (35 au in the best case). Optical images provide higher resolution, but the closest examples (AU Mic and β Pic) are edge-on, preventing the direct measurement of the azimuthal and radial disk structure that is required for fitting theoretical models of planetary perturbations. Here we report the detection of optical light reflected from the dust grains orbiting Fomalhaut (HD 216956). The system is inclined 24° away from edge-on, enabling the measurement of disk structure around its entire circumference, at a linear resolution of 0.5 au. The dust is distributed in a belt 25 au wide, with a very sharp inner edge at a radial distance of 133 au, and we measure an offset of 15 au between the belt's geometric centre and Fomalhaut. Taken together, the sharp inner edge and offset demonstrate the presence of planetary-mass objects orbiting Fomalhaut.