# Dynamical detection of a companion driving a spiral arm in a protoplanetary disk

**Authors:** Chen Xie, Bin B. Ren, Ruobing Dong, Élodie Choquet, Arthur Vigan, Jean-François Gonzalez, Kevin Wagner, Taotao Fang, Maria Giulia Ubeira-Gabellini  
**arXiv:** [2306.09279](https://arxiv.org/abs/2306.09279)  
**Date:** 2023-06-15  
**Summary page:** https://www.summarizepaper.com/fr/arxiv-id/2306.09279v1/

## Abstract

Radio and near-infrared observations have observed dozens of protoplanetary disks that host spiral arm features. Numerical simulations have shown that companions may excite spiral density waves in protoplanetary disks via companion-disk interaction. However, the lack of direct observational evidence for spiral-driving companions poses challenges to current theories of companion-disk interaction. Here we report multi-epoch observations of the binary system HD 100453 with the Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) facility at the Very Large Telescope. By recovering the spiral features via robustly removing starlight contamination, we measure spiral motion across 4 yr to perform dynamical motion analyses. The spiral pattern motion is consistent with the orbital motion of the eccentric companion. With this first observational evidence of a companion driving a spiral arm among protoplanetary disks, we directly and dynamically confirm the long-standing theory on the origin of spiral features in protoplanetary disks. With the pattern motion of companion-driven spirals being independent of companion mass, here we establish a feasible way of searching for hidden spiral-arm-driving planets that are beyond the detection of existing ground-based high-contrast imagers.