3I/ATLAS
The third confirmed interstellar object, discovered on 1 July 2025 by the ATLAS survey in Chile. Its orbit is the most strongly hyperbolic of the three found so far, with an eccentricity of roughly 6, and it showed cometary activity as it passed through the inner Solar System in late 2025. Some physical parameters remain preliminary, but its interstellar origin is established by the trajectory.
Note
Discovered in mid-2025; some physical parameters remain preliminary. The interstellar origin rests on the strongly hyperbolic orbit, not on any claim of artificial origin.
Physical & orbital character
How it was identified
Knowledge connections
- Trajectory classInterstellar Hyperbolic Trajectory
- Associated withExcess Hyperbolic Velocity
- Associated withIncoming-Trajectory Analysis
- Associated withSpectroscopic Composition Analysis
- Surveyed byATLAS
- Catalogued inMinor Planet Center
- Catalogued inNASA Jet Propulsion Laboratory
Sources
The primary and reference sources this topic draws on.
- Minor Planet CenterIAU Minor Planet Center
Designations and orbits of asteroids, comets, and minor bodies.
- NASA JPLJet Propulsion Laboratory / Solar System Dynamics
Orbital data, ephemerides, and small-body parameters for planets, asteroids, and comets.
- NASANational Aeronautics and Space Administration
Mission data, planetary science, space telescopes, and public-domain imagery.
Most NASA-produced imagery is in the public domain; individual items are checked for usage terms before publication.