arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1504.05461astro-ph.EP
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小行星家族年龄

Asteroid family ages

Federica Spoto, Andrea Milani, Zoran Knezevic

摘要:

一个新的族分类,其基础是用$\sim 384,000$编号的小行星的固有元素目录和新方法。对于$45$动态家庭与$>250$成员在此分类中确定,我们提出了一种尝试,以获得统计上显着的年龄:我们成功地计算年龄的$37$碰撞家庭。我们使用了一个严格的方法,包括一个最小二乘拟合的两侧的V形图在适当的半长轴,反直径平面,以确定相应的斜率,一个先进的误差模型的小行星直径的不确定性,迭代离群拒绝计划和质量控制。使用最佳可用的Yarkovsky测量来估计每个家族的Yarkovsky效应的校准。结果分别为起源于碎裂或撞击坑事件的家庭,年轻的,紧凑的家庭和截断,片面的家庭。对于所有计算的年龄,提供了相应的不确定性。我们发现两种情况下,两个独立的动力学家族一起形成一个单一的V形兼容的斜率,从而表明一个单一的碰撞事件。我们还发现了3个包含多个碰撞族的动力学族的例子,加上一个可疑的情况。我们已经发现了2个包含一个明显的亚科的族,这样就有可能测量一个明显的V形的斜率,从而确定二次碰撞的年龄。我们还提供了一些家庭中出现的核心差距的数据。本文计算的年龄是用统一的方法获得的,因此可以比较不同族的年龄,为小行星主带碰撞年代学提供了第一个实例。

英文摘要:

A new family classification, based on a catalog of proper elements with $\sim 384,000$ numbered asteroids and on new methods is available. For the $45$ dynamical families with $>250$ members identified in this classification, we present an attempt to obtain statistically significant ages: we succeeded in computing ages for $37$ collisional families. We used a rigorous method, including a least squares fit of the two sides of a V-shape plot in the proper semimajor axis, inverse diameter plane to determine the corresponding slopes, an advanced error model for the uncertainties of asteroid diameters, an iterative outlier rejection scheme and quality control. The best available Yarkovsky measurement was used to estimate a calibration of the Yarkovsky effect for each family. The results are presented separately for the families originated in fragmentation or cratering events, for the young, compact families and for the truncated, one-sided families. For all the computed ages the corresponding uncertainties are provided. We found 2 cases where two separate dynamical families form together a single V-shape with compatible slopes, thus indicating a single collisional event. We have also found 3 examples of dynamical families containing multiple collisional families, plus a dubious case. We have found 2 cases of families containing a conspicuous subfamily, such that it is possible to measure the slope of a distinct V-shape, thus the age of the secondary collision. We also provide data on the central gaps appearing in some families. The ages computed in this paper are obtained with a single and uniform methodology, thus the ages of different families can be compared, providing a first example of collisional chronology of the asteroid main belt.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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