AsteroidThermoPhysicalModels.jl

AsteroidThermoPhysicalModels.jl is a comprehensive Julia-based toolkit for thermophysical modeling (TPM) of asteroids. It allows you to simulate the temperature distribution of asteroids and predict non-gravitational perturbations on their dynamics (Yarkovsky and YORP effects).

📚 Documentation

For detailed documentation, please visit:

• Stable Documentation
• Development Documentation

Sample notebooks are available in Astroshaper-examples.

🚀 Installation

using Pkg
Pkg.add("AsteroidThermoPhysicalModels")
using AsteroidThermoPhysicalModels

Or in the Julia REPL package mode:

julia> ]  # Press ] to enter package mode
pkg> add AsteroidThermoPhysicalModels

🔍 Features

Thermophysical Processes

• Heat Conduction: 1-dimensional heat diffusion in depth direction
  • Multiple numerical solvers available (explicit Euler, implicit Euler, and Crank-Nicolson methods)
• Self-Shadowing: Local shadows cast by topography
• Self-Heating: Re-absorption of scattered and radiated photons by surrounding facets
• Binary Systems: Support for mutual shadowing (eclipses) and mutual heating between primary and secondary bodies

Shape Models

• Supports Wavefront OBJ format (*.obj)

Non-Gravitational Effects

• Yarkovsky Effect: Orbital perturbation due to asymmetric thermal emission
• YORP Effect: Rotational perturbation due to asymmetric thermal emission

Coming Soon (v0.2.0)

• Surface roughness modeling integration with AsteroidShapeModels.jl
• Enhanced heat conduction solver validation and benchmarks

🌟 Example

Temperature distribution of asteroid Didymos and its satellite Dimorphos:

📖 Basic Usage

using AsteroidShapeModels
using AsteroidThermoPhysicalModels


# Load an asteroid shape model
# - `path/to/shape.obj` is the path to your OBJ file (mandatory)
# - `scale` : scale factor for the shape model (e.g., 1000 for km to m conversion)
shape = load_shape_obj("path/to/shape.obj"; scale=1000)

# Set thermal parameters
thermo_params = ThermoParams(
    8.0 * 3600,  # Rotation period [s]
    0.05,        # Thermal skin depth [m]
    200.0,       # Thermal inertia [J m⁻² K⁻¹ s⁻¹/²]
    0.1,         # Reflectance in visible light [-]
    0.0,         # Reflectance in thermal infrared [-]
    0.9,         # Emissivity [-]
    0.5,         # Depth of lower boundary [m]
    0.0125,      # Depth step width [m]
    41           # Number of depth steps
)

# Create TPM model with solver selection
stpm = SingleAsteroidTPM(shape, thermo_params;
    SELF_SHADOWING = true,
    SELF_HEATING   = true,
    SOLVER         = CrankNicolsonSolver(thermo_params),  # Choose solver
    BC_UPPER       = RadiationBoundaryCondition(),
    BC_LOWER       = InsulationBoundaryCondition()
)

# Available solvers:
# - ExplicitEulerSolver(thermo_params)   # Fast but requires small time steps
# - ImplicitEulerSolver(thermo_params)   # Stable for any time step
# - CrankNicolsonSolver(thermo_params)   # Best accuracy

# Run simulation - see documentation for complete examples

📊 Output

The package produces detailed output files including:

• Surface and subsurface temperature distributions
• Thermal forces and torques
• Energy conservation metrics

🤝 Contributing

Contributions are welcome! Please feel free to submit a Pull Request.