Comparative Study of Mean-Motion Resonances in the Trans-Neptunian Region

✍ Scribed by M.D. Melita; A. Brunini

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 841 KB
• Volume: 147
• Category: Article
• ISSN: 0019-1035
• DOI: 10.1006/icar.2000.6414

✦ Synopsis

In this work we are interested in the present dynamical structure of the trans-neptunian region. It is known that at moderate to high eccentricities, stable orbits lie close to an exterior-mean-motion resonance with Neptune (NMMR). We study some NMMRs under different points of view. Intrinsic probabilities of collision and dynamical diffusion time-scales using frequency-map analysis have been computed. We have found that collisions and gravitational encounters by themselves would not produce remarkable differences between the number of objects orbiting in each resonance at present. However, frequency-map analysis reveals a much more robust region at the 2 : 3 NMMR than at the other NMMRs. Naturally the net orbital effect of the encounters can be enhanced differently in each individual NMMR due to differences in size of the stable niches, allowing the populations in the more unstable regions to evaporate sooner. We also study how certain evolutionary models, related with the orbital expansion of the outer planets during their formation stage, could result in resonant populations with a noticeably different primordial number of members. Finally, our results are discussed with reference to the present observational evidence and to our current understanding of the formation of the outer Solar System.