Yarkovsky Drift Detections for 247 Near-Earth Asteroids
Yarkovsky Drift Detections for 247 Near-Earth Asteroids
复制标题
雅可夫斯基漂移探测 247 颗近地小行星
作者：
A. Greenberg;J. Margot;A. Verma;P. Taylor;S. Hodge
雅可夫斯基效应是一个作用于小天体轨道的热过程，它会导致这些轨道随时间缓慢膨胀或收缩。这种影响是微妙的(对于直径1公里的对象，Au my−1)，因此通常很难测量。为了探测和量化雅可夫斯基效应，我们分析了600颗近地小行星(NEA)的光学和雷达天体测量。我们给出了247个近地天体的测量漂移率，这是已发表的最大的雅可夫斯基探测集。如此大的样本量为以统计方式检验雅可夫斯基效应提供了机会。特别是，我们描述了两个独立的基于总体的测试，它们验证了Yarkovsky轨道漂移的测量。首先，我们从观测上证实了Yarkovsky效应的理论尺寸依赖于1/D，其中D是直径。其次，我们发现，在我们的样本中观察到的负漂移率与正漂移率的比率为2.34，考虑到偏差和抽样不确定性，这意味着实际比率为。由于偶然性或统计噪声，这一比率发生的概率极小。观测到的逆行旋转体与前进旋转体的比率比从NEA人口研究的数字预测和关于来自各种主要带逃逸路线的近地天体旋转感的传统假设中预期的比率低两倍。我们还检查了太阳能转化为轨道能量的效率，并在我们的样本中发现了12%的中值效率。我们从NEA自旋和热性质的角度来解释这种效率。
The Yarkovsky effect is a thermal process acting upon the orbits of small celestial bodies, which can cause these orbits to slowly expand or contract with time. The effect is subtle ( au My−1 for a 1 km diameter object) and is thus generally difficult to measure. We analyzed both optical and radar astrometry for 600 Near-Earth Asteroids (NEAs) for the purpose of detecting and quantifying the Yarkovsky effect. We present 247 NEAs with measured drift rates, which is the largest published set of Yarkovsky detections. This large sample size provides an opportunity to examine the Yarkovsky effect in a statistical manner. In particular, we describe two independent population-based tests that verify the measurement of Yarkovsky orbital drift. First, we provide observational confirmation for the Yarkovsky effect’s theoretical size dependence of 1/D, where D is diameter. Second, we find that the observed ratio of negative to positive drift rates in our sample is 2.34, which, accounting for bias and sampling uncertainty, implies an actual ratio of . This ratio has a vanishingly small probability of occurring due to chance or statistical noise. The observed ratio of retrograde to prograde rotators is two times lower than the ratio expected from numerical predictions from NEA population studies and traditional assumptions about the sense of rotation of NEAs originating from various main belt escape routes. We also examine the efficiency with which solar energy is converted into orbital energy and find a median efficiency in our sample of 12%. We interpret this efficiency in terms of NEA spin and thermal properties.