Perihelion advance and Yarkovsky drift of near-Earth asteroids: asteroid physical properties, solar oblateness, and general relativity

提议小组将获得12颗近地小行星（NEAs）的高精度雷达距离和速度测量值，这些小行星的轨迹受到太阳光线、太阳形状和广义相对论的强烈影响。这些测量结果，结合该团队自2006年以来在先前的NSF奖励下获得的类似测量结果，将为当前的小行星物理、太阳物理和基础物理模型提供独特的观测约束。小行星轨道被太阳能的吸收和再发射所改变，这就是所谓的亚尔科夫斯基效应。这些变化将通过雷达测量来量化，以便约束近地天体的密度、组成和热性能。对NEA轨道的其他扰动来自太阳扁率的引力效应。雷达数据将通过测量这些小行星轨迹的变化，提供对太阳内部质量分布的直接探测。广义相对论（GR）的雷达测试也将通过量化接近太阳引力井深处的近地天体的近日点推进（apsidal进动）而得到改进。GR、太阳扁率和Yarkovsky机制的影响可以相互分离，因为它们对轨道半长轴、偏心、倾角和时间的依赖不同。大部分测量将由位于国家天文和电离层中心（NAIC）的阿雷西博望远镜上的行星雷达完成。将准备一份描述该项目的电脑简报，以便在阿雷西博游客中心、教师讲习班和其他场所传播。一名或多名研究生将在该项目中得到支持和培训，其成果将纳入本科课程。最后，这项工作所需的仔细校准可能会促进阿雷西博研究基础设施的改进。

The proposing team will obtain high-precision radar distance and velocity measurements for twelve near-Earth asteroids (NEAs) that have trajectories strongly affected by the light of the Sun, the shape of the Sun, and the effects of General Relativity. These measurements, combined with similar measurements that this team has been obtaining since 2006 under a previous NSF award, will provide unique observational constraints on current models of asteroid physics, solar physics, and fundamental physics. Asteroid orbits are altered by the absorption and reemission of solar energy, known as the Yarkovsky effect. These changes will be quantified with the radar measurements in order to constrain the densities, compositions, and thermal properties of NEAs. Other perturbations to NEA orbits arise from the gravitational effects of Solar oblateness. The radar data will provide a direct probe of the mass distribution in the Sun's interior by measuring these changes to the asteroid trajectories. Radar tests of general relativity (GR) will also be improved by quantifying the perihelion advance (apsidal precession) of NEAs that reach deep into the gravitational well of the Sun. The effects of GR, solar oblateness, and the Yarkovsky mechanism can be separated from each other because of their different dependences on orbital semi-major axis, eccentricity, inclination, and time. Most of the measurements will be performed with the planetary radar on the Arecibo telescope at the National Astronomy and Ionospheric Center (NAIC). A computer presentation describing the project will be prepared for dissemination at the Arecibo visitor center, teacher workshops, and other venues. One or more graduate students will be supported and trained in the project, and results will be incorporated in undergraduate courses. Finally, the careful calibration required for this work may prompt improvements to the research infrastructure at Arecibo.