Exploring the Collisional and Dynamical Evolution of Asteroids

AST-0909166 Bottke该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。使用最先进的数值模拟和当今的小行星属性，由Bottke博士领导的团队将调查自吸积结束以来碰撞和动力学演化如何塑造小天体种群。 这项工作遵循三个主题。 1)灶神星是一颗直径为530公里的完整分化小行星，目前在主带中是独一无二的，但有证据表明，原始主带曾经拥有多达1000颗灶神星样天体。 他们神秘消失的关键线索可以在今天的主带中的玄武岩，富含橄榄石和金属碎片中找到，研究小组将利用这些幸存的遗迹来深入了解失踪的灶神星人口的性质和演变。 2)外主带、希尔达和特洛伊星群分别包含15%、90%和90%的小行星，这些小行星的光谱数据被归类为D类或P类，它们是非常类似休眠彗星的原始天体，其起源存在争议。 将利用对这些小行星群演化的数值模拟来推断D/P小行星的性质，以检验各种起源假设。 3)小行星群的历史受到不同小行星家族的存在和演变的严重制约。 这里使用的研究工具包括Yarkovsky效应和YORP效应（科学家姓名的首字母缩写），这是分别导致小行星轨道半长轴漂移和自旋矢量改变的热辐射力和扭矩。 这项研究将跟踪Yarkovsky/YORP力的耦合动力学效应沿着碰撞效应，以模拟特定小行星家族的演变。 对于单个的小行星家族，研究小组将能够估计它们的初速度分布、年龄以及它们过去是否产生过“小行星簇射”。研究结果将影响对关键航天器数据的解释，并将有助于描述塑造和分散已知小行星、彗星和陨石的过程。 这项研究将被纳入科罗拉多和怀俄明州小学和高中的继续教育和公共宣传工作，并通过公众和业余天文学媒体进行。

AST-0909166BottkeThis award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Using state-of-the-art numerical simulations and present-day asteroid properties, the team led by Dr. Bottke will investigate how collisional and dynamical evolution has shaped small body populations since the end of accretion. The work follows three main themes. 1) Vesta, a 530 km diameter intact differentiated asteroid, is currently unique in the main belt, and yet evidence indicates that the primordial main belt once held as many as one thousand Vesta-like objects. Critical clues to their mysterious disappearance can be found among the basaltic, olivine-rich, and metallic fragments in the main belt today, and the team will use these surviving remnants to glean insights into the nature and evolution of the missing Vesta population. 2) The outer main belt, Hilda, and Trojan populations contain 15%, 90%, and 90% of the type of asteroid classified from spectral data as class D or P, primitive objects that closely resemble dormant comets and whose origin is controversial. Numerical simulations of the evolution of these populations to derive the nature of D/P asteroids will be used to test various origin scenarios. 3) The histories of asteroid populations are critically constrained by the existence and evolution of different asteroid families. The research tools used here include the Yarkovsky and YORP (an acronym of scientists' names) effects, which are thermal radiation forces and torques that cause asteroids to undergo orbital semi-major axis drift and spin vector modifications, respectively. This study will track the coupled dynamical effects of Yarkovsky/YORP forces along with collisional effects, to model the evolution of specific asteroid families. For individual families, the team will be able to estimate their initial velocity distributions, their ages, and whether or not they produced "asteroid showers" in the past.The results will affect the interpretation of critical spacecraft data and will help to characterize the processes that shaped and scattered known asteroids, comets, and meteorites. The research will be included in continuing educational and public outreach work in Colorado and Wyoming elementary and high schools, and through the public and amateur astronomy media.