ʻOumuamua
Interstellar object · 2017 U1
ʻOumuamua was the first recognised interstellar object, discovered by Pan-STARRS1 in October 2017. Its incoming speed and hyperbolic trajectory established that it was not bound to the Sun. Large brightness variations implied an extreme shape and tumbling, but no telescope resolved its surface. A small non-gravitational acceleration prompted natural outgassing models, including hydrogen released from radiation-processed ice; the exact composition and source system remain unknown.
Understand this world
How do we know ʻOumuamua came from another star system?ʻOumuamua’s speed and hyperbolic path established its interstellar origin. Separate those measurements from uncertain models of its shape, composition and acceleration. · 3 minMeasurements
- Effective diameter
- Not available
- Semimajor axis
- -1.272 AU
- Orbital period
- Not available
Orbit, physical values and uncertainties
- eccentricity
- 1.201133796102373 ± 2.1064E-5
- semi-major axis
- -1.27234500742808 au ± .00010015
- perihelion distance
- .2559115812959116 au ± 6.6635E-6
- inclination; angle with respect to x-y ecliptic plane
- 122.7417062847286 deg ± .00028826
- longitude of the ascending node
- 24.59690955523242 deg ± .00025422
- argument of perihelion
- 241.8105360304898 deg ± .0012495
- mean anomaly
- 51.1576197938249 deg ± .0061155
- time of perihelion passage
- 2458006.007321375231 TDB ± .00026424
- sidereal orbital period
- Not available
- mean motion
- .6867469493413392 deg/d ± 8.1084E-5
- aphelion distance
- Not available
- absolute magnitude
- 22.08 ± .44525
- rotation period
- 7.937 h
Published JPL orbital elements describe their stated epoch; they are not current positions. Small-body diameters can be effective/model-dependent sizes, not spherical shapes. Missing measurements remain unavailable. Pluto’s diameter uses the New Horizons reference rather than an empty SBDB field. Orbital epoch: JD 2458080.5 TDB.
Object reference ↗Missions & milestones
0 launches · 0 connected events
These are target-related flights and every connected programme record in the production catalogue. A connected event may concern another stage or target of the same journey. Launch outcome does not establish arrival or current operation.
No verified target-related flight is linked in the production catalogue.
Complete source cohort: 9,389 records.