Max-Planck-Institut für Sonnensystemforschung, 37077 Göttingen, Germany.
Department of Physics and Astronomy, University of Padova, 35122 Padova, Italy.
Science. 2015 Jan 23;347(6220):aaa1044. doi: 10.1126/science.aaa1044.
Images from the OSIRIS scientific imaging system onboard Rosetta show that the nucleus of 67P/Churyumov-Gerasimenko consists of two lobes connected by a short neck. The nucleus has a bulk density less than half that of water. Activity at a distance from the Sun of >3 astronomical units is predominantly from the neck, where jets have been seen consistently. The nucleus rotates about the principal axis of momentum. The surface morphology suggests that the removal of larger volumes of material, possibly via explosive release of subsurface pressure or via creation of overhangs by sublimation, may be a major mass loss process. The shape raises the question of whether the two lobes represent a contact binary formed 4.5 billion years ago, or a single body where a gap has evolved via mass loss.
罗塞塔号搭载的 OSIRIS 科学成像系统拍摄的图像显示，67P/楚留莫夫-格拉希门克彗星的核由两个通过短颈相连的裂片组成。该核的体密度小于水的一半。在距离太阳超过 3 个天文单位的地方，活动主要来自于颈部，那里一直可以看到喷流。核绕动量主轴旋转。表面形态表明，较大体积物质的移除，可能是通过内部压力的爆炸释放或升华形成悬垂物，这可能是主要的质量损失过程。该形状提出了一个问题，即这两个裂片是否代表 45 亿年前形成的接触双星，或者是通过质量损失演化出一个缺口的单个天体。
