First Neptune Trojan Discovered

The left-hand panel displays a bird's-eye view of the outer solar system, with the orbits of Jupiter (J), Saturn (S), Uranus (U), and Neptune (N) about the Sun shown schematically. The dark tube of points lying on Neptune's orbit marks the path of the newly discovered Trojan object 2001 QR322, relative to Neptune. The Trojan shuttles back and forth along Neptune's orbit as indicated by the red and green curved arrows. Each full shuttling takes about 10,000 years to complete. The small inset rectangle at left is magnified in the right-hand panel. When plotted over time, 2001 QR322 traces a local corkscrew pattern. The red curve traces the path of the Trojan as it travels away from Neptune, as indicated by the red arrows. The green curve traces the trajectory of the Trojan as it approaches Neptune. Each full twist of the corkscrew takes about the same time as Neptune takes to revolve around the Sun (166 years).