ʻOumuamua /ˌoʊmuˈɑːmuə/ — n. \ Interstellar object first detected traversing the Solar System; characterised by its highly elongated shape, anomalous non-gravitational acceleration, and absence of a visible coma.
Designated 1I/2017 U1, it exhibited physical and dynamical properties w/out precedent among known asteroids or comets, leading to speculation regarding its origin and the mechanisms driving its motion.
ʻOumuamua, from Hawaiian ~ “scout” / “messenger sent ahead,” derived from ʻou (“to reach for, to reach out”) and mua (“first, in advance”).
Orb. char.: perihelion ≈ 0.255 AU; eccentricity ≈ 1.20; hyperbolic excess velocity ≈ 26 km s⁻¹.
Disc.: 19 October 2017, by the Pan-STARRS 1 telescope, Haleakalā Observatory, Maui, Hawaii.