The YORP effect on 25 143 Itokawa
The YORP effect on 25 143 Itokawa
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DOI：
10.1051/0004-6361/200912543
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发表时间：
2009-11
影响因子：
6.5
通讯作者：
S. Breiter;P. Bartczak;M. Czekaj;B. Oczujda;D. Vokrouhlický
中科院分区：
文献类型：
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作者：
S. Breiter;P. Bartczak;M. Czekaj;B. Oczujda;D. Vokrouhlický
上下文小行星25143 Itokawa是在自转周期内探测Yarkovsky-O 'Keefe-Radzievskii-Paddack（YORP）效应的候选者之一。之前的研究是在196 608个小平面三角测量模型下进行的，无法对这种效应提供良好的理论估计，从而引发了有关网格分辨率和质量中心位置对旋转周期演变的影响的问题。目标。的YORP影响Itokawa计算不同的地形模型，以最高分辨率的3145728三角形面的Gaskell网格，试图找到最好的YORP估计。其他，低分辨率的模型也进行了研究，并重新审查的问题的依赖性的旋转周期漂移的密度分布的不均匀性。与433个具有类似分辨率的Eros模型进行了比较。方法.在旋转周期的YORP效应的数值模拟中，采用了Rubincam近似（零电导率）。假设开普勒日心运动和绕物体固定轴的均匀旋转，平均热辐射力矩在三角形小平面上求和。结果在Gaskell模型族中没有发现YORP收敛的证据。简化后的网格可能会很快收敛到它们的父模型，但这并不能证明从后者计算的YORP的质量。我们证实了高灵敏度的YORP效应的表面的细节为25 143 Itokawa和433爱神。的Itokawa YORP的质心移动的敏感性是弱于早期的作品，但相反的结果证明是敏感的自旋轴方向的身体框架。结论.要么YORP效应的敏感性是一种物理现象，所有目前的预测是值得怀疑的，或者目前的热模型过于简化。
Context. The asteroid 25143 Itokawa is one of the candidates for the detection of the Yarkovsky-O’Keefe-Radzievskii-Paddack (YORP) effect in the rotation period. Previous studies were carried out up to the 196 608 facets triangulation model and were not able to provide a good theoretical estimate of this effect, raising questions about the influence of the mesh resolution and the centre of mass location on the evolution the rotation period. Aims. The YORP effect on Itokawa is computed for different topography models up to the highest resolution Gaskell mesh of 3 145 728 triangular faces in an attempt to find the best possible YORP estimate. Other, lower resolution models are also studied and the question of the dependence of the rotation period drift on the density distribution inhomogeneities is reexamined. A comparison is made with 433 Eros models possessing a similar resolution. Methods. The Rubincam approximation (zero conductivity) is assumed in the numerical simulation of the YORP effect in rotation period. The mean thermal radiation torques are summed over triangular facets assuming Keplerian heliocentric motion and uniform rotation around a body-fixed axis. Results. There is no evidence of YORP convergence in Gaskell model family. Differently simplified meshes may converge quickly to their parent models, but this does not prove the quality of YORP computed from the latter. We confirm the high sensitivity of the YORP effect to the fine details of the surface for 25 143 Itokawa and 433 Eros. The sensitivity of the Itokawa YORP to the centre of mass shift is weaker than in earlier works, but instead the results prove to be sensitive to the spin axis orientation in the body frame. Conclusions. Either the sensitivity of the YORP effect is a physical phenomenon and all present predictions are questionable, or the present thermal models are too simplified.