Effect of Particle Traps on the Disk Chemistry and the Future Composition of Planets

Recent observations of protoplanetary disks reveal that substructures in the dust distribution of protoplanetary disks are common. These substructures show different forms, prevalence, locations, scales, and amplitudes around stars with different properties, such stellar luminosity and age (Andrews 2020). Although planet-disk interaction is a popular explanation for the origin of these structures, there are several theoretical alternatives and currently the real origin remains unknown (Pinilla & Youdin 2017), and planets have been only found in one protoplanetary disk (Keppler et al., 2018).

The purpose of this project is to use chemical models together with hydrodynamical and dust evolution models as crucial keys to differentiate between all these models for the origin of the observed substructures. This research is timely with the new ALMA MAPS data and the incoming ALMA AGE-PRO data, which aim to map the chemical structures and constrain the properties of the gas reservoirs on planet-forming scales, in a variety of protoplanetary disks.

Parametric studies of disk chemistry with simple prescriptions of gas and dust have shown that depletions of dust and gas make those parts of the disk more transparent to stellar and external radiation (UV and X-rays), and therefore these regions become warmer. This will have a direct influence on the locations of the ice lines of different abundant volatiles, such as water and carbon-monoxide, and as a consequence it will also affect the composition of the planets forming within these disks.

Contrary, in the regions where particles concentrate, the disk temperature decrease and some volatiles are sequestered in the grains (Facchini et al., 2018, Alarcón et al., 2020). Current chemical models have only explored in detail the case of planet-disk interaction, with several simplifications. In this thesis, we will explore the effect of different origins of pressure bumps in the disk, including planets, dead zones, zonal flows, and vortices.

We aim to understand how the nature of such pressure bumps (when they form, how long they live, amplitude, location) affects the gas and dust distribution, the disk temperature and the chemical abundances of several volatiles in protoplanetary disks. We place interest on particular atomic and molecular lines. For instance, the carbon-to-oxygen ratio is one of the few planetary properties which can provide useful information on the formation history of a planet, and it can be measure both in planets and disks (e.g., Madhusudhan et al., 2012, Bergin et al., 2016).