论文标题
太阳邻居中散装陆生外行组合物范围的合理限制
Plausible constraints on the range of bulk terrestrial exoplanet compositions in the Solar neighbourhood
论文作者
论文摘要
岩石行星组成通过影响核心大小,地幔特性和熔化行为来调节行星的演变。然而,分类研究的这一方面的定量治疗通常仍然不足。我们试图限制太阳街区(<200 PC)中潜在的散装陆生外行组合物的范围。我们基于Hypatia和Galah目录中恒星化学丰度的种群分析来限制可能的岩石系外行星组成。我们使用一个悬浮的模型来模拟假设的,陆地型系外行星的组成,在阳光状恒星周围可居住的区域中,考虑到O,S,S,Na,Si,Mg,Fe,Fe,Ni,CA和Al的元素。我们通过假设持续的氧赋形性进一步应用核心套管分化,并使用Gibbs能量最小化算法对随之而来的地幔矿物学进行建模。我们报告了几个组成参数的统计数据,并提出了一组(21)个代表性行星组成,用于在迫在眉睫的建模和实验研究中使用为末端成员组成。我们发现恒星Fe/mg与金属核心尺寸之间有很强的相关性,这可能从18至35 wt%不等。此外,恒星MG/SI给出了地幔矿物学的一阶指示,高Mg/Si星星导致较弱,富含铁蛋白酶的地幔较弱,而低毫克/SI的恒星可导致机械上更强的地幔。调节地壳浮力和地幔斜纹二烯的元素Na受到最大的影响。尽管我们发现行星披风主要由Fe/mg硅化物组成,但核心矿物的核心大小和相对丰度在系外行星之间可能差异很大。这些差异可能导致太阳街区岩石系外行星之间的进化途径不同。
Rocky planet compositions regulate planetary evolution by affecting core sizes, mantle properties, and melting behaviours. Yet, quantitative treatments of this aspect of exoplanet studies remain generally under-explored. We attempt to constrain the range of potential bulk terrestrial exoplanet compositions in the solar neighbourhood (<200 pc). We circumscribe probable rocky exoplanet compositions based on a population analysis of stellar chemical abundances from the Hypatia and GALAH catalogues. We apply a devolatilization model to simulate compositions of hypothetical, terrestrial-type exoplanets in the habitable zones around Sun-like stars, considering elements O, S, Na, Si, Mg, Fe, Ni, Ca, and Al. We further apply core-mantle differentiation by assuming constant oxygen fugacity, and model the consequent mantle mineralogy with a Gibbs energy minimisation algorithm. We report statistics on several compositional parameters and propose a reference set of (21) representative planet compositions for using as end-member compositions in imminent modelling and experimental studies. We find a strong correlation between stellar Fe/Mg and metallic core sizes, which can vary from 18 to 35 wt%. Furthermore, stellar Mg/Si gives a first-order indication of mantle mineralogy, with high-Mg/Si stars leading to weaker, ferropericlase-rich mantles, and low-Mg/Si stars leading to mechanically stronger mantles. The element Na, which modulates crustal buoyancy and mantle clinopyroxene fraction, is affected by devolatilization the most. While we find that planetary mantles mostly consist of Fe/Mg-silicates, core sizes and relative abundances of common minerals can nevertheless vary significantly among exoplanets. These differences likely lead to different evolutionary pathways among rocky exoplanets in the solar neighbourhood.