# Building protoplanetary disks from the molecular cloud: redefining the disk timeline

## TL;DR

This paper models the formation and evolution of protoplanetary disks from molecular clouds, revealing new insights into planet trapping mechanisms and establishing a timeline comparison with the traditional MMSN model.

## Contribution

It introduces a hydrodynamical simulation of disk formation from molecular clouds, linking collapse phases to planet migration and trapping, and redefines the disk timeline relative to MMSN.

## Key findings

- Planets can be trapped at heat transition barriers and sublimation lines.
- Giant planets may form and be trapped at a few AU during collapse.
- The collapse-formed disk is approximately 2 Myr older than MMSN.

## Abstract

We study the formation of the protoplanetary disk by the collapse of a primordial molecular cloud, and how its evolution leads to the selection of specific types of planets. We use a hydrodynamical code that accounts for the dynamics, thermodynamics, geometry, and composition of the disk to numerically model its evolution as it is fed by the infalling cloud material. As the mass accretion rate of the disk onto the star determines its growth, we can calculate the stellar characteristics by interpolating its radius, luminosity, and temperature over the stellar mass from pre-calculated stellar evolution models. The density and midplane temperature of the disk then allow us to model the interactions between the disk and potential planets and determine their migration. At the end of the collapse phase, when the disk reaches its maximum mass, it pursues its viscous spreading, similarly to the evolution from a minimum mass solar nebula (MMSN). In addition, we establish a timeline equivalence between the MMSN and a "collapse-formed disk" that would be older by about 2 Myr. We can save various types of planets from a fatal type-I inward migration: in particular, planetary embryos can avoid falling on the star by becoming trapped at the heat transition barriers and at most sublimation lines (except the silicates one). One of the novelties concerns the possible trapping of putative giant planets around a few astronomical units from the star around the end of the infall. Moreover, trapped planets may still follow the traps outward during the collapse phase and inward after it. Finally, this protoplanetary disk formation model shows the early possibilities of trapping planetary embryos at disk stages that are anterior by a few million years to the initial state of the MMSN approximation.