Are the E-type asteroids (2867) Steins, a target of the Rosetta mission, and NEA (3103) Eger remnants of an old asteroid family?
Are the E-type asteroids (2867) Steins, a target of the Rosetta mission, and NEA (3103) Eger remnants of an old asteroid family?
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罗塞塔任务的目标 E 型小行星 (2867) 斯坦因和 NEA (3103) 埃格尔是古老小行星家族的残余物吗？
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
A. Migliorini
中科院分区：
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作者：
S. Fornasier;F. Marzari;E. Dotto;M. Barucci;A. Migliorini
目标。我们研究了E型小行星2867 Steins和3103埃格的光谱特性，前者是Rosetta使命的主要带目标，后者是近地小行星。这两个物体之间的光谱相似性表明，尽管它们目前的轨道不同，但可能有共同的起源。我们探讨的可能性，斯坦斯和埃格都是一个古老的小行星家族的残余物，在约2.36 Au的母体解体的结果。埃格可能是在雅科夫斯基效应和共振的驱动下进入了一个穿越地球的轨道。方法.用欧洲南方天文台的3.5米新技术望远镜进行了可见光范围内的低分辨率光谱学研究。我们使用数值积分的SWIFT-RMVSY，它考虑到昼夜和季节的Yarkovsky效应，模拟虚拟家庭片段的动力学演变。结果Steins和埃格的光谱非常相似，都显示出E[II]亚群典型的以0.49 μm为中心的吸收特征。由于吸收深、光谱斜率大，它们在亚类中是独特的。它们可能是一个古老的侵蚀小行星家族的成员，该家族形成于现在的斯坦斯位置附近。数值轨道积分表明，在目前的Steins轨道（可能是该家族中最大的遗迹）和像埃格这样的穿越地球的轨道之间存在一条动力学路径。
Aims. We have investigated the spectral properties of the E-type asteroids 2867 Steins, a main belt object target of the Rosetta mission, and 3103 Eger, a near Earth asteroid. The strong spectral similarity between these two objects suggests a possible common origin in spite of their presently different orbits. We explore the possibility that Steins and Eger are both remnants of an old asteroid family, the outcome of the breakup of a parent body at about 2.36 AU. Eger possibly moved into an Earth-crossing orbit driven by the Yarkovsky effect and resonances. Methods. Low resolution spectroscopy in the visible range was carried out with the 3.5 m New Technology Telescope (NTT) of the European Southern Observatory. We used the numerical integrator SWIFT-RMVSY, which takes into account the diurnal and seasonal Yarkovsky effect, to simulate the dynamical evolution of fictitious family fragments. Results. The spectra of Steins and Eger are very similar, and both show an absorption feature centered at 0.49 µm typical of the E[II] subgroup. They are peculiar among the subgroup because of the deep absorption feature and steep spectral slope. They may be members of an old eroded asteroid family which formed close to the present location of Steins. Numerical orbital integrations show that there is a dynamical pathway between the present orbit of Steins, possibly the largest remnant of the family, and Earth-crossing orbits like that of Eger.