Interstellar Origin Confirmed: Welcome to 3I/ATLAS
After two weeks of intensive observations, the Minor Planet Center has officially confirmed the object's hyperbolic orbit, designating it as C/2025 N1 (ATLAS), or simply 3I/ATLAS - humanity's third confirmed interstellar visitor.
Official Confirmation
The International Astronomical Union's Minor Planet Center has officially announced the discovery and interstellar nature of C/2025 N1 (ATLAS), now designated as 3I/ATLAS. The "3I" prefix indicates this is the third interstellar object (Interstellar designation) to be discovered passing through our Solar System.
This confirmation comes after 603 high-quality observations collected over a 104-day observation arc, providing exceptional precision in determining its orbital parameters.
Hyperbolic Orbit Confirmed
The key evidence for interstellar origin is the object's orbital eccentricity of 6.1396 ± 0.0008. An eccentricity greater than 1.0 indicates a hyperbolic orbit - meaning the object is not gravitationally bound to the Sun and will eventually escape our Solar System.
Confirmed Orbital Parameters
- Eccentricity: 6.1396 ± 0.0008 (hyperbolic)
- Perihelion: 1.3564 ± 0.0001 AU (October 29, 2025)
- Semi-major axis: -0.26392 ± 0.00002 AU (negative = unbound)
- Hyperbolic excess velocity (v∞): 58 km/s
- Inclination: 175.11° (retrograde orbit)
- Velocity at perihelion: 68.3 km/s
Only the Third Interstellar Visitor
3I/ATLAS joins an exclusive club of confirmed interstellar objects:
- 1I/'Oumuamua (2017): The first confirmed interstellar object, discovered in October 2017. It showed no cometary activity and had an elongated shape, sparking intense scientific debate.
- 2I/Borisov (2019): Discovered in August 2019, this was clearly a comet with active outgassing, showing that Solar System-like comets exist around other stars.
- 3I/ATLAS (2025): Our current visitor, showing strong cometary activity and providing the best opportunity yet to study an interstellar comet in detail.
Journey Through the Solar System
Based on the confirmed orbit, 3I/ATLAS will:
- Reach perihelion (closest to Sun) on October 29, 2025 at 1.357 AU
- Pass closest to Earth on December 19, 2025 at a safe distance of 1.80 AU (269 million km)
- Pass within 0.0179 AU of Mars' orbit around October 2, 2025
- Exit the Solar System forever, returning to interstellar space in 2026
Where Did It Come From?
Initial trajectory analysis suggests 3I/ATLAS likely originated from the Milky Way's thin disk or thick disk. If it came from the thick disk, the comet could be over 7 billion years old - older than our 4.6-billion-year-old Solar System.
The comet has been traveling through interstellar space for potentially billions of years before its brief passage through our Solar System.
Scientific Significance
This confirmation has triggered unprecedented international cooperation. Every major space telescope and ground-based observatory is being mobilized to study 3I/ATLAS during its months-long passage through our Solar System. This represents a once-in-a-generation opportunity to study pristine material from another star system.
Unlike 1I/'Oumuamua, which was discovered as it was already leaving, and 2I/Borisov which was detected relatively late, 3I/ATLAS was found early enough to plan comprehensive observation campaigns with the best instruments available to humanity.