cubewano

Cubewano is an informal designation for a class of trans-Neptunian objects known as classical Kuiper belt objects. The term derives from the prototype object 1992 QB1, whose discovery in 1992 by David Jewitt and Jane Luu helped reveal a population of icy bodies beyond Neptune. Cubewanos are part of the Kuiper belt but are not in strong mean-motion resonance with Neptune and are not part of the scattered or resonant populations. They represent the relatively stable, long-lived members of the belt.

Orbital characteristics of cubewanos typically place them at semi-major axes around 42 to 47 astronomical units, with low to moderate eccentricities and low to moderate inclinations. They generally have perihelia well beyond the orbits of the giant planets and are not strongly perturbed by Neptune on solar-system timescales. Because of their non-resonant, less dynamically excited orbits, cubewanos provide important clues about the primordial outer solar system and the early migration of Neptune.

The classical Kuiper belt is often subdivided into a cold population and a hot population. Cold cubewanos have low inclinations (often a few degrees) and small eccentricities, while hot cubewanos show higher inclinations and larger eccentricities, though they remain non-resonant. Physical properties vary widely: sizes range from tens to well over a thousand kilometers, and many show red optical colors and icy surface components. Some cubewanos exist as tight binary systems.

In modern usage, cubewano remains common in literature, though the formal term preferred is classical Kuiper belt object. They contrast with resonant bodies, such as plutinos, and with scattered-disc objects.