论文标题
系外球场是否有区别？
Are exoplanetesimals differentiated?
论文作者
论文摘要
在白矮人的大气中观察到的金属表明，许多人最近具有积聚的行星体。在某些情况下，观察到的组合物表明材料从分化的行星体的核心（或地幔）中占主导地位。分化的系外球菌之间的碰撞会产生此类碎片。在这项工作中，我们利用了大量的白色矮人，在这些白矮人中至少检测到了一种辅助脂肪（热爱核心）和一种岩石卵石（喜欢岩石）的物种，以评估通常类型的外甲虫区分。我们利用N体模拟在行星系统的碰撞演化过程中跟踪核心和地幔材料的命运，以表明大多数差异化行星的残余物保留了与父母相似的核心分数，而有些则是极其富含核心或地幔富丽石的。 Comparison with the white dwarf data for calcium and iron indicates that the data are consistent with a model in which $66^{+4}_{-6}\%$ have accreted the remnants of differentiated planetesimals, whilst $31^{+5}_{-5}\%$ have Ca/Fe abundances altered by the effects of heating (although the former can be as high as $ 100 \％$，如果忽略加热）。这些结论假设单个身体污染，并且碰撞进化保留了各种行星系统的相似特征。这些结果表明，碰撞和差异化是系术系统中的关键过程。我们强调需要具有精确确定的金属丰度的较大污染的白色矮人样本，以更好地理解系外系统的分化过程。
Metals observed in the atmospheres of white dwarfs suggest that many have recently accreted planetary bodies. In some cases, the compositions observed suggest the accretion of material dominantly from the core (or the mantle) of a differentiated planetary body. Collisions between differentiated exoplanetesimals produce such fragments. In this work, we take advantage of the large numbers of white dwarfs where at least one siderophile (core-loving) and one lithophile (rock-loving) species have been detected to assess how commonly exoplanetesimals differentiate. We utilise N-body simulations that track the fate of core and mantle material during the collisional evolution of planetary systems to show that most remnants of differentiated planetesimals retain core fractions similar to their parents, whilst some are extremely core-rich or mantle-rich. Comparison with the white dwarf data for calcium and iron indicates that the data are consistent with a model in which $66^{+4}_{-6}\%$ have accreted the remnants of differentiated planetesimals, whilst $31^{+5}_{-5}\%$ have Ca/Fe abundances altered by the effects of heating (although the former can be as high as $100\%$, if heating is ignored). These conclusions assume pollution by a single body and that collisional evolution retains similar features across diverse planetary systems. These results imply that both collisions and differentiation are key processes in exoplanetary systems. We highlight the need for a larger sample of polluted white dwarfs with precisely determined metal abundances to better understand the process of differentiation in exoplanetary systems.
