Transcript Slide 1
Origin of the Structure of the Kuiper Belt During a Dynamical Instability in the Orbits of Uranus and Neptune (“the Nice Model”) Levison, H., Morbidelli, A., VanLaerhoven, C., Gomes, R., & Tsiganis, K. Icarus, Accepted Nathan Kaib 5/16/08 Outline • Description of Kuiper Belt • Giant Planet Migration and the Nice Model • Simulation Results • Conclusions Outline • Description of Kuiper Belt • Giant Planet Migration and the Nice Model • Simulation Results • Conclusions Properties of the Kuiper Belt • Missing Mass: KB only contains 0.01 – 0.1 Earth masses • Need 2-3 orders of magnitude more mass to accrete 1001000 km bodies Properties of the Kuiper Belt • 10 – 50% of objects found in resonances with Neptune • Inclinations extend up to ~40o Properties of the Kuiper Belt • Contains large population of excited orbits that do not pass near planets now - Scattered Disk Properties of the Kuiper Belt • Contains double peaked inclination distribution: -“Hot” population Hot Cold -“Cold” population Properties of the Kuiper Belt • Hot and Cold populations have different properties Hot Bluer, Larger Cold Redder, Smaller Properties of the Kuiper Belt • Cold, low e population has sharp cutoff at 1:2 resonance with Neptune Outline • Description of Kuiper Belt • Giant Planet Migration and the Nice Model • Simulation Results • Conclusions Planetesimal Scattering Outer Planet Migration N J • Nep, Ura, and Sat much more likely to scatter bodies in than eject them U S • Jupiter’s energy kicks are powerful enough to eject most bodies Outer Planet Migration Neptune, Uranus, and Saturn migrate outwards and Jupiter moves in to conserve angular momentum Current Planet Configuration 1:2 MMR Saturn currently is ~1.3 AU beyond the 1:2 MMR with Jupiter The Nice Model 1:2 MMR ~35 AU If there were 10’s of Earth masses of material beyond Neptune originally, then Saturn must have crossed the 1:2 MMR with Jupiter • Saturn crossing 1:2 MMR causes orbits of U and N to become chaotic • Dynamical friction due to scattering damps re-circurlarizes orbits Nice Model Can Explain… • Cataclysmic Late Heavy Bombardment 3.8 Gyrs ago • High inclinations of Jovian Trojans • Existence of cometary bodies in main asteroid belt • Significant non-zero inclinations and eccentricities of giant planets • Irregular satellite populations of giant planets Nice Model Can Explain… • Cataclysmic Late Heavy Bombardment 3.8 Gyrs ago • High inclinations of Jovian Trojans • Existence of cometary bodies in main asteroid belt • Significant non-zero inclinations and eccentricities of giant planets • Irregular satellite populations of giant planets Nice Model Can Explain… • Cataclysmic Late Heavy Bombardment 3.8 Gyrs ago • High inclinations of Jovian Trojans • Existence of cometary bodies in main asteroid belt • Significant non-zero inclinations and eccentricities of giant planets • Irregular satellite populations of giant planets Nice Model Can Explain… • Cataclysmic Late Heavy Bombardment 3.8 Gyrs ago • High inclinations of Jovian Trojans • Existence of cometary bodies in main asteroid belt • Significant non-zero inclinations and eccentricities of giant planets • Irregular satellite populations of giant planets Nice Model Can Explain… • Cataclysmic Late Heavy Bombardment 3.8 Gyrs ago • High inclinations of Jovian Trojans • Existence of cometary bodies in main asteroid belt • Significant non-zero inclinations and eccentricities of giant planets • Irregular satellite populations of giant planets Outline • Description of Kuiper Belt • Giant Planet Migration and the Nice Model • Simulation Results • Conclusions Simulations • Start planets at last scattering between Uranus and Neptune • Surround Neptune’s orbit with torus of 60,000 test particles extending to 34 AU • Vary Neptune’s starting place and edamping in sims Simulations Observed Simulated Results Summary Kuiper Belt Mass: Bimodal Inclinations: Simulations predict 0.05 to 0.14 Earth masses Inclinations and eccentricities reproduced well Distribution of a and q reproduced Reproduced Physical Differences in Hot and Cold Pops: 1:2 Resonance Cold Boundary: Cold and Hot bodies originate in different areas Cold pops. all stop near 1:2 MMR Resonant Populations: Scattered Disk: Results Summary Kuiper Belt Mass: Bimodal Inclinations: Simulations predict 0.05 to 0.14 Earth masses Inclinations and eccentricities reproduced well Distribution of a and q reproduced Reproduced Physical Differences in Hot and Cold Pops: 1:2 Resonance Cold Boundary: Cold and Hot bodies originate in different areas Cold pops. all stop near 1:2 MMR Resonant Populations: Scattered Disk: Results Summary Kuiper Belt Mass: Bimodal Inclinations: Simulations predict 0.05 to 0.14 Earth masses Inclinations and eccentricities reproduced well Distribution of a and q reproduced Reproduced Physical Differences in Hot and Cold Pops: 1:2 Resonance Cold Boundary: Cold and Hot bodies originate in different areas Cold pops. all stop near 1:2 MMR Resonant Populations: Scattered Disk: Observed Simulated Results Summary Kuiper Belt Mass: Bimodal Inclinations: Simulations predict 0.05 to 0.14 Earth masses Inclinations and eccentricities reproduced well, Numbers? Distribution of a and q reproduced Reproduced Physical Differences in Hot and Cold Pops: 1:2 Resonance Cold Boundary: Cold and Hot bodies originate in different areas Cold pops. all stop near 1:2 MMR Resonant Populations: Scattered Disk: Results Summary Kuiper Belt Mass: Bimodal Inclinations: Simulations predict 0.05 to 0.14 Earth masses Inclinations and eccentricities reproduced well, Numbers? Distribution of a and q reproduced Reproduced Physical Differences in Hot and Cold Pops: 1:2 Resonance Cold Boundary: Cold and Hot bodies originate in different areas Cold pops. all stop near 1:2 MMR Resonant Populations: Scattered Disk: Observed Simulated Results Summary Kuiper Belt Mass: Bimodal Inclinations: Simulations predict 0.05 to 0.14 Earth masses Inclinations and eccentricities reproduced well, Numbers? Distribution of a and q reproduced Reproduced Physical Differences in Hot and Cold Pops: 1:2 Resonance Cold Boundary: Cold and Hot bodies originate in different areas Cold pops. all stop near 1:2 MMR Resonant Populations: Scattered Disk: Results Summary Kuiper Belt Mass: Bimodal Inclinations: Simulations predict 0.05 to 0.14 Earth masses Inclinations and eccentricities reproduced well, Numbers? Distribution of a and q reproduced Reproduced Physical Differences in Hot and Cold Pops: 1:2 Resonance Cold Boundary: Cold and Hot bodies originate in different areas Cold pops. all stop near 1:2 MMR Resonant Populations: Scattered Disk: Results Summary Kuiper Belt Mass: Bimodal Inclinations: Simulations predict 0.05 to 0.14 Earth masses Inclinations and eccentricities reproduced well, Numbers? Distribution of a and q reproduced Reproduced Physical Differences in Hot and Cold Pops: 1:2 Resonance Cold Boundary: Cold and Hot bodies originate in different areas Cold pops. all stop near 1:2 MMR Resonant Populations: Scattered Disk: Results Summary Kuiper Belt Mass: Bimodal Inclinations: Simulations predict 0.05 to 0.14 Earth masses Inclinations and eccentricities reproduced well, Numbers? Distribution of a and q reproduced Reproduced Physical Differences in Hot and Cold Pops: 1:2 Resonance Cold Boundary: Cold and Hot bodies originate in different areas Cold pops. all stop near 1:2 MMR Resonant Populations: Scattered Disk: Hot Cold Results Summary Kuiper Belt Mass: Bimodal Inclinations: Simulations predict 0.05 to 0.14 Earth masses Inclinations and eccentricities reproduced well, Numbers? Distribution of a and q reproduced Reproduced Physical Differences in Hot and Cold Pops: 1:2 Resonance Cold Boundary: Cold and Hot bodies originate in different areas Cold pops. all stop near 1:2 MMR Resonant Populations: Scattered Disk: Results Summary Kuiper Belt Mass: Bimodal Inclinations: Simulations predict 0.05 to 0.14 Earth masses Inclinations and eccentricities reproduced well, Numbers? Distribution of a and q reproduced Reproduced Physical Differences in Hot and Cold Pops: 1:2 Resonance Cold Boundary: Cold and Hot bodies originate in different areas Cold pops. all stop near 1:2 MMR Resonant Populations: Scattered Disk: Observed Simulated Results Summary Kuiper Belt Mass: Bimodal Inclinations: Simulations predict 0.05 to 0.14 Earth masses Inclinations and eccentricities reproduced well, Numbers? Distribution of a and q reproduced Reproduced Physical Differences in Hot and Cold Pops: 1:2 Resonance Cold Boundary: Cold and Hot bodies originate in different areas Cold pops. all stop near 1:2 MMR Resonant Populations: Scattered Disk: Conclusions • Nice Model reproduces more properties of Kuiper Belt than any other previous scenario • Eccentricities of cold belt too high by a factor of 2 • May be due to unaccounted for physics such as collisional damping