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

提出建议的小组将获得12颗近地小行星的高精度雷达距离和速度测量结果，这些小行星的轨道受到太阳光、太阳形状和广义相对论的影响。这些测量结果，加上该团队自2006年以来在之前的NSF奖项下获得的类似测量结果，将为当前的小行星物理学，太阳物理学和基础物理学模型提供独特的观测约束。小行星的轨道会因吸收和再发射太阳能而改变，这被称为雅科夫斯基效应。将用雷达测量对这些变化进行量化，以限制近地小行星的密度、成分和热特性。近地小行星轨道的其他摄动来自太阳扁率的引力效应。雷达数据将通过测量小行星轨道的这些变化，直接探测太阳内部的质量分布。还将通过量化深入太阳引力阱的近地小行星的近日点推进（近点进动）来改进广义相对论的雷达测试。由于GR、太阳扁率和Yarkovsky机制对轨道半长轴、偏心率、倾角和时间的依赖性不同，它们的影响可以相互分离。大部分测量将使用国家天文学和电离层中心（NAIC）阿雷西沃望远镜上的行星雷达进行。将准备一份描述该项目的计算机演示文稿，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，其结果将纳入本科课程。最后，这项工作所需的仔细校准可能会促使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.