PA3Py — Pebble Accretion Post-Processing for TripodPy

PA3Py is a Python post-processing package for computing pebble accretion growth of planetary embryos from TripodPy hydrodynamic disk simulations. It is not a standalone disk evolution code — it reads TripodPy HDF5 output snapshots and computes embryo growth on top of them.

The physics follows Ormel (2017) and Drążkowska et al. (2023), including headwind/shear regime switching, 2D–3D turbulence transition, Safronov ballistic onset, and a dynamic isolation mass cap.

Please read the documentation for a full description.

Installation

Option 1: Install from PyPI (Recommended)

You can easily install the latest stable version of PA3Py using pip:

pip install pa3py

Option 2: Install from Source

If you want to modify the source code or get the latest development version, you can clone the repository:

git clone https://github.com/mmmaxii/PA3Py.git
cd PA3Py
pip install .

For an editable installation (recommended during development):

pip install -e ".[dev]"

Requirements

• Python ≥ 3.9
• TripodPy simulation output (HDF5 snapshots)
• numpy, scipy, h5py, matplotlib

Quick Start

from pa3py import PA3Py

sim = PA3Py("path/to/tripodpy/output/")

# Run pebble accretion for embryos at 2, 5, 10, 20 AU
results = sim.run_growth([2.0, 5.0, 10.0, 20.0])

# Hovmöller diagram (dust-to-gas ratio vs time)
sim.plot_hovmoller(field='epsilon')

For custom chemistry (multi-snowline, 4-species):

from pa3py import PA3Py, FunctionComposition
from pa3py import constants as c

def my_chemistry(r_cm, t_sec):
    if r_cm < 3.0 * c.AU:
        return {'silicates': 1.0}
    elif r_cm < 5.0 * c.AU:
        return {'silicates': 0.5, 'H2O': 0.5}
    else:
        return {'silicates': 0.3, 'H2O': 0.3, 'CO2': 0.4}

sim = PA3Py("path/to/output/", comp_model=FunctionComposition(my_chemistry))
results = sim.run_growth([5.0, 10.0, 20.0])

Physics & References

• Ormel (2017): The Emerging Paradigm of Pebble Accretion
• Drążkowska et al. (2023): Planet Formation Theory in the Era of ALMA and Kepler

Acknowledgements

PA3Py was developed at the Pontificia Universidad Católica de Chile by Maximiliano Valderrama Vargas. Contact: mvalderrav@uc.cl