# SagittariusA*s
> **Part of the [Celestial](https://celestial4498-prog.github.io/Celestial/) project.**
A Rust simulation engine for Sagittarius A\*, the supermassive black hole at the center of the Milky Way. Models spacetime geometry, accretion physics, relativistic jets, gravitational lensing, and shadow observables using real astrophysical parameters constrained by EHT observations.
## Features
- **Kerr spacetime** — Full metric tensor, geodesic integration in geometrized units (RK4), event/Cauchy horizons, ergosphere
- **Accretion disk** — Shakura-Sunyaev, ADAF, and Slim disk models with temperature profiles, surface density, radiative efficiency
- **Relativistic jets** — Blandford-Znajek power, Doppler boosting, apparent superluminal motion, synchrotron cooling
- **Gravitational lensing** — Einstein radius, image positions, magnification, Shapiro delay, strong-field bending
- **Black hole shadow** — Critical impact parameter, shadow contour, asymmetry, angular size, EHT diameter prediction
- **Radiation** — Planck radiance, Wien peak, bremsstrahlung, Eddington luminosity
- **General relativity** — Lorentz factor, time dilation, length contraction, gravitational redshift, gravitational waves
- **Singularity physics** — Schwarzschild/Kerr/Reissner-Nordström classification, Hawking temperature, Bekenstein entropy, Penrose energy extraction
## Quick Start
```bash
cargo build
cargo run
```
## Examples
```bash
cargo run --example accretion_disk_sim # Accretion disk luminosity comparison (SS vs ADAF)
cargo run --example jet_viewer # Relativistic jet diagnostics
cargo run --example sagittarius_shadow # EHT shadow prediction
```
## Testing
```bash
cargo test --all-targets
```
69 integration tests covering engine, observables, and physics modules.
## Project Structure
```
src/
├── config/ # Physical constants and Sgr A* parameters
├── engine/ # Spacetime geometry, accretion disk, jet dynamics
├── observables/ # Lensing, radiation, shadow computations
├── physics/ # Gravitation, relativity, singularity models
└── utils/ # Math helpers, I/O
```
## Dependencies
- [sciforge](https://crates.io/crates/sciforge) — Physical constants, astronomical utilities
## License
MIT — see [LICENSE](LICENSE).