Modeling the planetary heat transport of small bodies in the early Solar System allows us to understand the geological context of meteorite samples. Conductive cooling in planetesimals is controlled by thermal conductivity, heat capacity, and density, which are functions of temperature (T). We investigate if the incorporation of the T‐dependence of thermal properties and the introduction of a nonlinear term to the heat equation could result in different interpretations of the origin of different classes of meteorites. We have developed a finite difference code to perform numerical models of a conductively cooling planetesimal with T‐dependent properties and find that including T‐dependence produces considerable differences in thermal history, and in turn the estimated timing and depth of meteorite genesis. We interrogate the effects of varying the input parameters to this model and explore the nonlinear T‐dependence of conductivity with simple linear functions. Then we apply non‐monotonic functions for conductivity, heat capacity, and density fitted to published experimental data. For a representative calculation of a 250 km radius pallasite parent body, T‐dependent properties delay the onset of core crystallization and dynamo activity by ∼40 Myr, approximately equivalent to increasing the planetary radius by 10%, and extend core crystallization by ∼3 Myr. This affects the range of planetesimal radii and core sizes for the pallasite parent body that are compatible with paleomagnetic evidence. This approach can also be used to model the T‐evolution of other differentiated minor planets and primitive meteorite parent bodies and constrain the formation of associated meteorite samples.

中文翻译：

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具有温度相关特性的小行星的传导冷却

对早期太阳系中小天体的行星热传输进行建模可以使我们了解陨石样品的地质背景。通过热导率，热容和密度（以温度（T）的函数）控制以小行星形式进行的传导冷却。我们研究是否将热特性的T依赖性并入热方程引入非线性项是否可能导致对不同类别陨石起源的不同解释。我们已经开发了一个有限差分代码，以执行具有T依赖特性的传导冷却行星的数值模型，并发现其中包括T依赖关系在热历史上产生了很大的差异，进而估计了陨石成因的时间和深度。我们询问了改变输入参数对该模型的影响，并通过简单的线性函数探索了电导率的非线性T依赖性。然后，我们将非单调函数用于拟合已发布的实验数据的电导率，热容量和密度。对于方圆250 km的辉石母体T的代表性计算依赖的特性将核心结晶和发电机活动的开始延迟了约40 Myr，大约相当于将行星半径增加了10％，并使核心结晶扩展了约3 Myr。这会影响与古磁性证据兼容的方铁母体的小行星半径范围和核心尺寸。这种方法也可以用来模拟其他分化小行星和原始陨石母体的T演化，并限制相关陨石样品的形成。