# hannorein/rebound

💫 An open-source multi-purpose N-body code.

Repository: https://github.com/hannorein/rebound
Canonical: https://ross.abutalabs.com/products/hannorein-rebound
Homepage: https://rebound.hanno-rein.de/
Language: C
License: GPL-3.0
License Family: copyleft
Topics: astrophysics, n-body, planetary-science, symplectic-integrator, keplerian-elements, orbits
Last push: 2026-08-26T11:17:35+00:00

## Health v2 (maintenance only)
Score: 93/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 99, release rhythm 82, longevity 100
- inputs: {"age_days": 5541, "days_push": 7, "days_rel": 42, "gap_med": 31.0, "n_releases_24m": 15}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1122, forks 267 (observed 2026-08-28T04:03:39.997683+00:00)

## What it is
REBOUND is an open-source N-body integration library for simulating the gravitational motion of particles such as stars, planets, moons, and dust. It is written in C99 with an easy-to-use Python module, offering many symplectic and high-accuracy integrators, collision detection, and real-time 3D visualization.

## Use cases
- simulate the solar system over billions of years
- integrate planetary system dynamics with close encounters
- model orbits of planets, moons, and dust particles
- run collisional granular dynamics simulations
- couple user-defined ODEs like tides and spin to N-body dynamics
- teach orbital mechanics with runnable browser examples
- fast long-term integrations of planetary systems with AVX512

## When to choose
- you need a flexible, dependency-free N-body integrator in C or Python
- you want symplectic or high-accuracy adaptive integrators for gravitational dynamics
- you need collision detection and granular dynamics support
- you want pip-installable scientific simulation with visualization

## When to avoid
- you need general-purpose molecular dynamics or non-gravitational force simulation
- you need a GUI-first simulation tool rather than a library
- your problem involves electromagnetism or fluid dynamics rather than gravity

## Facets
- artifact type: library
- maturity: active
- function: simulation, graphics, sdk
- domain: astronomy, simulation
- platform: windows, python, c, cross-platform
- tags: n-body, astrophysics, orbital-mechanics, symplectic-integrators, planetary-dynamics, gravitational-dynamics, physics, scientific-computing, linux, macos

## Member repositories
- hannorein/rebound (main) score 93

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:03:39.997683+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T06:40:55.649393+00:00, confidence not recorded.
  - readme: https://github.com/hannorein/rebound (fetched 2026-08-28T04:03:39.997683+00:00, sha 27a07837ba1d)
  - homepage: https://rebound.hanno-rein.de/ (fetched 2026-08-29T12:44:38.371495+00:00, sha 39e0e85e86c8)
  - site_page: https://rebound.hanno-rein.de/quickstart/installation (fetched 2026-08-29T12:44:38.381215+00:00, sha 7385a66a2134)
  - site_page: https://rebound.hanno-rein.de/quickstart/firstexample (fetched 2026-08-29T12:44:38.383480+00:00, sha 8c867f60d55c)
  - site_page: https://rebound.hanno-rein.de/quickstart/whereto (fetched 2026-08-29T12:44:38.385343+00:00, sha c7134fce3bf5)
  - site_page: https://rebound.hanno-rein.de/api (fetched 2026-08-29T12:44:38.386898+00:00, sha b1a25bd74f6d)
  - site_page: https://rebound.hanno-rein.de/changelog (fetched 2026-08-29T12:44:38.388516+00:00, sha a347573f1381)
  - site_page: https://rebound.hanno-rein.de/ipython_examples/HybridIntegrationsWithTRACE (fetched 2026-08-29T12:44:38.391278+00:00, sha fe7ec808542d)
- Data as of 2026-08-30T08:39:29.467469+00:00.