Modeling dust condensation in protoplanetary disks

行星形成的第一步是尘埃从原行星盘中的气体中凝结而成。尘埃凝结的地点和方式将决定行星的组成。太阳系的内行星是在高温下形成的。因此，与太阳相比，它们的挥发性元素较少。以前对尘埃凝结的研究受到了一系列理想化的限制，这些理想化的研究是为了使计算更容易。这些理想化包括每个元素的单一冷凝温度或忽略气体盘的演化。他们可能限制了模型中元素的数量，或者忽略了系统的热历史。提出的工作是建立比以前的模型包含更多元素的更高保真度的模型，并将原行星盘的物理和发展纳入其中。这项工作的结果将与我们太阳系中的元素丰度进行比较，以更好地了解我们太阳系形成的条件，并将用于预测系外行星系统中行星组成的变化。该团队将通过包括博士后学者和研究生来帮助培训未来的天文学家（并增加STEM劳动力）。他们还将扩大他们的外联工作，包括在拉斯维加斯举办社区明星派对，以及一个受欢迎的“天文直播”项目。该团队将结合现有的两种代码，对原行星盘中的尘埃凝结进行新的建模。第一个是原行星盘演化代码，由参与该项目的一位博士后编写。另一个是热力学代码，叫做GRAINS，它模拟了给定热力学条件下尘埃颗粒的凝结顺序。产生的合并代码将被称为动态磁盘尘埃冷凝（DDDC）代码。代码中的一个创新将是将气体压力作为磁盘位置和时间的函数。这将改变给定元素的冷凝温度作为时间和位置的函数。由此产生的代码将被用来模拟我们自己的太阳系的形成，通过使用太阳平均元素丰度作为输入参数。然后，研究小组将观察观测到的变化，因为它们改变了各种参数，包括圆盘的质量、角速度、核心温度、热历史和总体组成。结果将与太阳系的值进行比较，以约束我们太阳系的早期热历史。他们还将研究不同的磁盘组成，以检查系外行星系统中可能存在的变化。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The first step in planet formation is when dust condenses from gasses in a protoplanetary disk. Where and how the dust condenses will determine the composition of the planets. The inner planets of our Solar System formed at high temperature. As a result, they are depleted in volatile elements compared to the Sun. Previous studies of dust condensation have been limited by a series of idealizations that were made to make the computation easier. These idealizations included a single condensation temperature for each element or neglecting the evolution of the gas disk. They might have limited the number of elements in the model or ignored the thermal history of the system. The proposed work is to build higher-fidelity models that incorporate many more elements than previous models, and which incorporate the physics and development of the protoplanetary disk. The results of this work will be compared to elemental abundances in our Solar System to better understand the conditions in which our Solar System formed and will be used to predict variations in planetary composition in exoplanetary systems. The team will help to train future astronomers (and increase the STEM workforce) by including postdoctoral scholars and graduate students. They will also expand on their outreach efforts, including neighborhood star parties in Las Vegas, and a popular "Astronomy on Tap" program.The team will combine two existing codes to undertake new modeling of dust condensation in protoplanetary disks. The first is a protoplanetary disk evolution code written by one of the postdocs who will work on the project. The other is a thermodynamic code called GRAINS which models the condensation sequence of dust particles under given thermodynamic conditions. The resulting merged code will be called the Dynamical Disk Dust Condensation (DDDC) code. One of the innovations in the code will be the incorporation of gas pressure as a function of position in the disk and time. This will have the effect of altering the condensation temperature for a given element as a function of time and position. The resulting code will be used to model the formation of our own Solar System by using solar mean elemental abundances as input parameters. The team will then look at changes in observables as they change various parameters, including mass of the disk, angular velocity, temperature in the core, as well as thermal history and bulk composition. The results will be compared to Solar System values to constrain the early thermal history of our Solar System. They will also look at different disk compositions to examine what variations might exist in exoplanetary systems.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.