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AsteriaStar
Interstellar object

1I/ʻOumuamua

The first confirmed interstellar object, detected in October 2017 on its way out of the Solar System. Its strongly hyperbolic orbit (eccentricity about 1.2) showed it was never bound to the Sun. It displayed no visible coma, is highly elongated, and showed a slight non-gravitational acceleration — features that drew wide attention, though the scientific consensus is that it is a natural body.

Confirmed interstellarHyperbolic (e ≈ 1.20) — unbound

Note

The unusual shape and slight non-gravitational acceleration prompted speculation about an artificial origin; that speculation is not supported by the evidence, and the scientific consensus is a natural body (an ejected planetesimal or comet-like fragment).

Physical & orbital character

Origin:Approached from the general direction of the constellation Lyra; no specific parent star has been identified
Activity:No visible coma or tail; a small non-gravitational acceleration was measured
Size:Highly elongated; very roughly 100–400 m on its long axis (uncertain)
Composition:Dry, reddened surface; no gas or dust detected

Knowledge connections

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.

  • NASA ADSNASA Astrophysics Data System

    Bibliographic index of peer-reviewed astronomy and astrophysics literature.