The Extreme Kuiper Belt Binary 2001 QW322

Description

orbit determination of 2001 QW 322 , a Kuiper Belt binary with a very large separation whose properties challenge binary-formation and evolution theories. Six years of tracking indicate that the binary's mutual orbit period is ≈25-30 years, that the orbit pole is retrograde and inclined 50-62 • from the ecliptic plane, and, most surprisingly, that the mutual orbital eccentricity is < 0.4. The semimajor axis of 105,000-135,000 km is 10 times that of other near-equal mass binaries. Because this weakly bound binary is prone to or-bital disruption by interlopers, its lifetime in its present state is likely less than 1

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