An object in a high-eccentricity orbit close to the ecliptic plane beyond Neptune; also known as a scattered Kuiper Belt object (SKBO). SDOs have perihelia close to Neptune’s orbit but aphelia extending out to 100 au or more. The first SDO to be discovered was 1996 TL₆₆, now numbered (15874), which has a perihelion of 35.0 au, aphelion 131.2 au, eccentricity 0.58, inclination 24°.0, and a period of 758 years. Such objects may have escaped from the Kuiper Belt or have been planetesimals scattered from their point of origin between Uranus and Neptune. The dwarf planet Eris is an SDO.