# Formation of Gaps in Self-Gravitating Debris Disks by Secular Resonance in a Single-planet System I: A Simplified Model

**Authors:** Antranik A. Sefilian, Roman R. Rafikov, Mark C. Wyatt  
**arXiv:** [2010.15617](https://arxiv.org/abs/2010.15617)  
**Date:** 2020-10-29  
**Summary page:** https://www.summarizepaper.com/en/paper/2010.15617v1/

## Key points

- Debris disks exhibit complex morphologies such as gaps, spirals and warps.
- Existing models focus on the role of massive perturbers but often ignore the gravitational effects of the disk itself.
- Researchers investigate the secular interaction between an eccentric planet and a massive external debris disk using an analytical model that accounts for both the gravitational coupling between the disk and planet and the disk's self-gravity.
- Secular resonances within the disk can occur where planetesimal eccentricities become significantly excited even when the disk is less massive than the planet.
- Double-ringed debris disks like those around HD 107146 and HD 92945 could be formed by secular resonances with yet-undetected planets inside them.
- The team characterizes how properties of these resonances depend on planet and disk parameters and finds that this mechanism is robust provided that the disk is sufficiently massive.
- Applying their results to HD 107146 reveals that this mechanism readily produces non-axisymmetric gaps about 20 astronomical units wide.
- The findings may help set constraints on total mass in double-ringed debris disks.

## Summary

Debris disks are known to exhibit complex morphologies such as gaps, spirals and warps. Existing models for explaining these features focus on the role of massive perturbers like planets and stellar companions, but often ignore the gravitational effects of the disk itself. In this study, researchers investigate the secular interaction between an eccentric planet and a massive external debris disk using an analytical model that accounts for both the gravitational coupling between the disk and planet and the disk's self-gravity. Surprisingly, even when the disk is less massive than the planet, secular resonances within the disk can occur where planetesimal eccentricities become significantly excited. The authors propose that double-ringed debris disks like those around HD 107146 and HD 92945 could be formed by secular resonances with yet-undetected planets inside them. The team characterizes how properties of these resonances (locations, timescales, widths) depend on planet and disk parameters and finds that this mechanism is robust provided that the disk is sufficiently massive. Applying their results to HD 107146 reveals that this mechanism readily produces non-axisymmetric gaps about 20 astronomical units wide. The findings may help set constraints on total mass in double-ringed debris disks; for example, considering perturbations from a known brown dwarf companion leads to an inferred mass of approximately 170 Earth masses for HD 206893.