# Forming planetary systems that contain only minor planets

**Authors:** Dimitri Veras, Shigeru Ida  
**arXiv:** [2409.16354](https://arxiv.org/abs/2409.16354)  
**Date:** 2024-09-24  
**Summary page:** https://www.summarizepaper.com/en/paper/2409.16354v1/

## Key points

- Researchers investigate formation of planetary systems composed solely of minor planets
- Focus on systems with undetectably low planetary masses around main-sequence stars and metal-polluted white dwarfs
- Simulations show significant portion of initial parameter space allows for configurations with sub-Earth-mass bodies
- Success linked to initial dust mass in the system
- Model aligns well with theoretical predictions and known aspects of modern exoplanet populations
- Discuss common classes of exoplanets in the Milky Way (Super-Earths, Mini-Neptunes, gas giants)
- Highlight phenomena like inward migration and "Neptunian desert"
- Suggest minor planet-only systems may be more prevalent in our galaxy than previously thought

## Summary

The researchers in this study investigate the formation of planetary systems composed solely of minor planets, providing new insights into an unexplored aspect of exoplanet populations. Due to limitations in observing low-mass planets in our galaxy, the team focuses on systems with undetectably low planetary masses found around main-sequence stars and metal-polluted white dwarfs. Through simulations involving accretion and migration processes, they demonstrate that a significant portion of initial parameter space allows for configurations with entirely sub-Earth-mass bodies to form. This success is closely tied to the initial dust mass present in the system. By extrapolating their model to observed exoplanet systems, the researchers show that their code aligns well with theoretical predictions and known aspects of modern exoplanet populations. They discuss key features such as Super-Earths and Mini-Neptunes being common classes of exoplanets in the Milky Way, along with gas giants forming close to their host stars. Additionally, they highlight phenomena like inward migration and the "Neptunian desert," showcasing how their simulations capture trends seen in actual exoplanetary systems. Overall, this study suggests that minor planet-only systems may be more prevalent throughout our galaxy than previously thought. These findings not only contribute to our understanding of planetary system formation but also offer insights into unresolved questions regarding planet-hosting white dwarfs and metal-polluted white dwarfs in our galaxy.