The influence of global self-heating on the Yarkovsky and YORP effects
The influence of global self-heating on the Yarkovsky and YORP effects
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全球自热对 Yarkovsky 和 YORP 效应的影响
DOI：
10.1093/mnras/stt750
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发表时间：
2012
影响因子：
4.8
通讯作者：
S. Green
中科院分区：
文献类型：
--
作者：
B. Rozitis;S. Green
除了碰撞和引力之外，越来越多的证据表明，吸收太阳光的不对称反射和热再辐射产生的光子反冲力是小型小行星物理和动力学演化的主要机制。雅可夫斯基效应会导致轨道漂移，而雅可夫斯基-奥基夫-拉齐耶夫斯基-帕达克（YORP）效应会导致旋转速率和极方向的变化。我们提出了一种改进的高级热物理模型，可以在不规则形状小行星的大凹腔内发生的全球自加热的情况下同时预测雅可夫斯基和 YORP 效应，这种现象在所有以前的模型中都被忽略或忽略。它还与粗糙表面热红外光束效应相结合，先前已证明这种效应可以增强雅可夫斯基轨道漂移，并将 YORP 旋转加速度平均抑制数十个百分点。对所有已发表的近地小行星凹形模型以及 100 高斯随机球体的测试表明，雅可夫斯基效应对阴影和全球自热效应的敏感度为百分之几或更低。为简单起见，如果所需的精度水平是这个量级，雅可夫斯基模型可以忽略这些影响。与雅可夫斯基效应不同，YORP 效应对阴影和全局自热效应非常敏感。其灵敏度随着 YORP 自转加速度相对强度的降低而增加，并且似乎不太依赖于小行星的凹度。全球自加热往往会在小行星的 YORP 旋转加速度与倾角曲线中产生垂直偏移，该偏移与阴影效应产生的方向相反。它还确保至少存在一个临界倾斜角，在该倾斜角处 YORP 旋转加速度为零。如果小行星表现出较大的阴影效应，则必须包括全球自加热才能准确预测 YORP 效应。如果不包括全局自热效应，那么在约 75% 的情况下，如果也不包括阴影，会产生更好的预测。此外，全球自加热会降低 YORP 效应预测对小行星形状模型详细变化的敏感性。
In addition to collisions and gravitational forces, there is a growing amount of evidence that photon recoil forces from the asymmetric reflection and thermal re-radiation of absorbed sunlight are primary mechanisms that are fundamental to the physical and dynamical evolution of small asteroids. The Yarkovsky effect causes orbital drift, and the Yarkovsky–O’Keefe–Radzievskii–Paddack (YORP) effect causes changes in the rotation rate and pole orientation. We present an adaptation of the Advanced Thermophysical Model to simultaneously predict the Yarkovsky and YORP effects in the presence of global self-heating that occurs within the large concavities of irregularly shaped asteroids, which has been neglected or dismissed in all previous models. It is also combined with rough surface thermal-infrared beaming effects, which have been previously shown to enhance the Yarkovsky orbital drift and dampen on average the YORP rotational acceleration by orders of several tens of per cent. Tests on all published concave shape models of near-Earth asteroids, and also on 100 Gaussian random spheres, show that the Yarkovsky effect is sensitive to shadowing and global self-heating effects at the few per cent level or less. For simplicity, Yarkovsky models can neglect these effects if the level of accuracy desired is of this order. Unlike the Yarkovsky effect, the YORP effect can be very sensitive to shadowing and global self-heating effects. Its sensitivity increases with decreasing relative strength of the YORP rotational acceleration, and does not appear to depend greatly on the degree of asteroid concavity. Global self-heating tends to produce a vertical offset in an asteroid's YORP-rotational-acceleration versus obliquity curve which is in opposite direction to that produced by shadowing effects. It also ensures that at least one critical obliquity angle exists at which zero YORP rotational acceleration occurs. Global self-heating must be included for accurate predictions of the YORP effect if an asteroid exhibits a large shadowing effect. If global self-heating effects are not included, then it is found in ~75 per cent of cases that better predictions are produced when shadowing is also not included. Furthermore, global self-heating has implications for reducing the sensitivity of the YORP effect predictions to detailed variations in an asteroid's shape model.
未结合小行星对 7343-154634 的物理和动力学特征
影响因子：
6.5
作者：
Duddy S
通讯作者：
Duddy S