Margot J L, Nolan M C, Benner L A M, Ostro S J, Jurgens R F, Giorgini J D, Slade M A, Campbell D B
California Institute of Technology, MC 150-21, Pasadena, CA 91125, USA.
Science. 2002 May 24;296(5572):1445-8. doi: 10.1126/science.1072094. Epub 2002 Apr 11.
Radar images of near-Earth asteroid 2000 DP107 show that it is composed of an approximately 800-meter-diameter primary and an approximately 300-meter-diameter secondary revolving around their common center of mass. The orbital period of 1.755 +/- 0.007 days and semimajor axis of 2620 +/- 160 meters constrain the total mass of the system to 4.6 +/- 0.5 x 10(11) kilograms and the bulk density of the primary to 1.7 +/- 1.1 grams per cubic centimeter. This system and other binary near-Earth asteroids have spheroidal primaries spinning near the breakup point for strengthless bodies, suggesting that the binaries formed by spin-up and fission, probably as a result of tidal disruption during close planetary encounters. About 16% of near-Earth asteroids larger than 200 meters in diameter may be binary systems.
近地小行星2000 DP107的雷达图像显示，它由一个直径约800米的主星体和一个直径约300米的次星体组成，二者围绕它们的共同质心旋转。其1.755±0.007天的轨道周期和2620±160米的半长轴将该系统的总质量限制在4.6±0.5×10¹¹千克，主星体的堆积密度为1.7±1.1克每立方厘米。这个系统以及其他双体近地小行星的主星体呈球状，在无强度物体的解体点附近旋转，这表明这些双体是由加速旋转和裂变形成的，可能是在近距离行星交会期间受到潮汐破坏的结果。直径大于200米的近地小行星中约16%可能是双体系统。
