Modeling dust condensation in protoplanetary disks

University Of Nevada Las Vegas, Las Vegas NV

Investigators

Abstract

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.