# Stirred but not shaken: a multi-wavelength view of HD 16743's debris disc

**Authors:** Jonathan P. Marshall, Julien Milli, Elodie Choquet, Carlos del Burgo, Grant M. Kennedy, Francisca Kemper, Mark C. Wyatt, Quentin Kral, Remi Soummer  
**arXiv:** [2303.17128](https://arxiv.org/abs/2303.17128)  
**Date:** 2023-03-30  
**Summary page:** https://www.summarizepaper.com/en/paper/2303.17128v1/

## Key points

- The study focuses on planetesimals, which are building blocks of planets and source of dust, ice, and gas in debris discs.
- Planets have a significant influence on the dynamics of planetesimals, sculpting the orbits of debris belts to produce asymmetries or gaps.
- High spatial resolution imaging of debris discs can help constrain the architecture of planetary systems and infer the presence of unseen planetary companions.
- The research team conducted a study on HD 16743, a relatively young F-type star that hosts a bright edge-on debris disc.
- New observations using HST and ALMA revealed that HD 16743's disc is highly inclined with a radial extent of 157.7 au and an FWHM of 79.4 au ($\Delta R/R = 0.5$).
- The vertical scale height of the disc is significantly greater than typically assumed unstirred value for such discs.
- These findings suggest that stirring may be occurring within HD 16743's disc by bodies at least several times more massive than Pluto up to 18.3 $M_{\oplus}$ in the single object limit, indicating possible unseen planetary companions within this system.
- This study provides valuable insights into how planets interact with planetesimals to shape debris disks and offers new opportunities for understanding the architecture of planetary systems.

## Summary

The study focuses on planetesimals, which are the building blocks of planets in protoplanetary discs and the source of dust, ice, and gas in debris discs. Along with planets, they make up the leftover material after star formation that constitutes a planetary system. Planets have a significant influence on the dynamics of planetesimals, sculpting the orbits of debris belts to produce asymmetries or gaps. High spatial resolution imaging of debris discs can help constrain the architecture of planetary systems and infer the presence of unseen planetary companions. The research team conducted a study on HD 16743, a relatively young F-type star that hosts a bright edge-on debris disc. Previous observations with far-infrared Herschel suggested that its disc was stirred by a planetary companion. The team presented new spatially resolved observations at near-infrared and millimeter wavelengths using HST and ALMA, respectively. The results revealed that HD 16743's disc is highly inclined at $87\fdg3~^{+1\fdg9}_{-2\fdg5}$ with a radial extent of 157.7$^{+2.6}_{-1.5}$ au and an FWHM of 79.4$^{+8.1}_{-7.8}$ au ($\Delta R/R = 0.5$). The vertical scale height of the disc is $0.13~\pm~0.02$, significantly greater than typically assumed unstirred value of 0.05 for such discs . These findings suggest that stirring may be occurring within HD 16743's disc by bodies at least several times more massive than Pluto up to 18.3 $M_{\oplus}$ in the single object limit, indicating possible unseen planetary companions within this system . Overall , this study provides valuable insights into how planets interact with planetesimals to shape debris disks and offers new opportunities for understanding the architecture of planetary systems .