论文标题
家族和非家庭小行星的共同起源
The common origin of family and non-family asteroids
论文作者
论文摘要
目前，所有小行星都被归类为源于已知尸体或非家庭的破坏的家庭。一个杰出的问题是这些非家庭小行星的起源。它们是单独形成的，还是作为已知家庭的成员形成的，但是是混乱的轨道，还是旧幽灵家族的成员，即具有共同父母的小行星，但轨道不再聚集在轨道元素空间中？在这里，我们表明，内带中非家族小行星的大小与它们的轨道偏心率相关，并与它们的倾向相关，这表明非家族和家庭小行星都来自少数大型原始星球。我们估计，内部主带中约有85％的小行星来自植物群，维斯塔，尼萨，波拉纳和尤拉利亚家庭，其余约15％来自相同的家庭，或者更有可能是一些鬼家庭。这些新结果表明，我们必须在几个大型前体体的进化史中对各种陨石群体的不同特征寻求解释。我们的发现还支持这样的模型，即小行星通过质体磁盘中物质的重力崩溃而形成大的模型。
All asteroids are currently classified as either family, originating from the disruption of known bodies, or non-family. An outstanding question is the origin of these non-family asteroids. Were they formed individually, or as members of known families but with chaotically evolving orbits, or are they members of old ghost families, that is, asteroids with a common parent body but with orbits that no longer cluster in orbital element space? Here, we show that the sizes of the non-family asteroids in the inner belt are correlated with their orbital eccentricities and anticorrelated with their inclinations, suggesting that both non-family and family asteroids originate from a small number of large primordial planetesimals. We estimate that ~85% of the asteroids in the inner main belt originate from the Flora, Vesta, Nysa, Polana and Eulalia families, with the remaining ~15% originating from either the same families or, more likely, a few ghost families. These new results imply that we must seek explanations for the differing characteristics of the various meteorite groups in the evolutionary histories of a few, large, precursor bodies. Our findings also support the model that asteroids formed big through the gravitational collapse of material in a protoplanetary disk.
