Rotation rates of Kuiper-belt objects from their light curves
Rotation rates of Kuiper-belt objects from their light curves
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DOI：
10.1038/18168
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发表时间：
1999-03
期刊：
影响因子：
64.8
通讯作者：
W. Romanishin;S. Tegler
中科院分区：
文献类型：
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作者：
W. Romanishin;S. Tegler
由于柯伊伯带天体相对较小且距离地球较远，人们对它们的物理特性知之甚少。例如，直径为300公里的柯伊伯带天体在典型的距离为~ 30au时，其夹角仅为0.014弧秒。因此，只有通过它们反射的光（它们的光曲线）的变化，才能研究它们的表面标记、形状和旋转特性。本文报道了柯伊伯带天体的光学光曲线。只有在观测中最微弱的物体上才观察到变化。我们可以排除食双星和表面标记的变化作为这些光曲线的起源，这表明观察到的变化是由于不规则形状的物体的旋转。不规则的形状可能仅限于最小的柯伊伯带天体，因为它们内部区域的物质强度足以在上面物质的重量下保持形状。然而，如果我们调查的所有天体本质上大小相同，那么本质上最微弱的天体可能由比明亮的天体更强、更暗的物质组成。
Very little is known about the physical properties of Kuiper-belt objects, due to their relatively small size and large distance from the Earth. For example, a Kuiper-belt object with a diameter of 300 km at a typical distance of ∼30AUwould subtend an angle of only 0.014 arcsec. It is therefore possible to investigate their surface markings, shapes and rotational properties only through variations in the light that they reflect (their light curves). Here we report a survey of optical light curves from Kuiper-belt objects. Variations are observed only for the faintest objects in the survey. We can rule out eclipsing binary objects and variations in the surface markings as the origin of these light curves, suggesting that the observed variations are due to the rotation of irregularly shaped objects. Irregular shapes may be limited to the smallest Kuiper-belt objects because the material strength in their inner regions is sufficient to maintain the shape against the weight of the overlying material. If, however, all of the objects in our survey are of essentially the same size, then the intrinsically faintest ones may be composed of a stronger and darker material than the brighter ones.