Evidence for the formation of comet 67P/Churyumov-Gerasimenko through gravitational collapse of a bound clump of pebbles
Evidence for the formation of comet 67P/Churyumov-Gerasimenko through gravitational collapse of a bound clump of pebbles
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DOI：
10.1093/mnras/stx2741
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发表时间：
2017-07-01
影响因子：
4.8
通讯作者：
Snodgrass, Colin
中科院分区：
文献类型：
--
作者：
Blum, Juergen;Gundlach, Bastian;Snodgrass, Colin
导致太阳系中行星体形成的过程仍然没有完全了解。利用欧洲航天局罗塞塔使命上的全套仪器获得的结果，我们提出的证据表明，彗星67 P/Churyumov-Gerasimenko可能是通过一个毫米大小的尘埃聚集体（“鹅卵石”）的束缚团块的温和引力坍缩形成的，与微观冰粒混合。这一形成设想导致彗星的组成同时符合全球孔隙度、均匀性、抗拉强度、热惯性、垂直温度分布、所释放尘埃的大小和孔隙度以及水蒸气产生率随日心距离减小而急剧增加的情况，这是由罗塞塔号航天器和菲莱号着陆器上的仪器测量的。我们的研究结果表明，在年轻恒星周围的原行星盘中观察到的大量鹅卵石为彗星和其他小型天体提供了建筑材料。
The processes that led to the formation of the planetary bodies in the Solar system are still not fully understood. Using the results obtained with the comprehensive suite of instruments onboard the European Space Agency's Rosetta mission, we present evidence that comet 67P/Churyumov-Gerasimenko likely formed through the gentle gravitational collapse of a bound clump of mm-sized dust aggregates ('pebbles'), intermixed with microscopic ice particles. This formation scenario leads to a cometary make-up that is simultaneously compatible with the global porosity, homogeneity, tensile strength, thermal inertia, vertical temperature profiles, sizes and porosities of emitted dust and the steep increase in water-vapour production rate with decreasing heliocentric distance, measured by the instruments onboard the Rosetta spacecraft and the Philae lander. Our findings suggest that the pebbles observed to be abundant in protoplanetary discs around young stars provide the building material for comets and other minor bodies.