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

提出建议的团队将获得12颗近地小行星(NEA)的高精度雷达距离和速度测量，这些小行星的轨迹受到太阳光线、太阳形状和广义相对论效应的强烈影响。这些测量，再加上这个团队自2006年以来一直在获得的类似测量，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。小行星的轨道被太阳能的吸收和再发射所改变，这就是众所周知的雅可夫斯基效应。这些变化将通过雷达测量进行量化，以限制近地小行星的密度、组成和热性质。近地天体轨道的其他扰动是由太阳扁率的引力效应引起的。雷达数据将通过测量小行星轨迹的这些变化，直接探测太阳内部的质量分布。广义相对论(GR)的雷达测试也将通过量化深入太阳引力井的近日点推进(近地点进动)而得到改进。由于GR、太阳扁率和Yarkovsky机制对轨道半长轴、偏心率、倾角和时间的不同依赖关系，它们的影响可以相互分离。大多数测量将使用国家天文和电离层中心(NAIC)阿雷西博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、教师研讨会和其他场所传播。一名或多名研究生将在该项目中得到支持和培训，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的研究基础设施得到改进。

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.