index of $2.41\pm0.17$. This value is typical of debris disks and indicates a power-law index of the grain size distribution $q=3.27\pm0.10$, close to predictions for a classical collisional cascade.'
author:
- 'David J. Wilner'
- 'Meredith A. MacGregor'
- 'Sean M. Andrews'
- 'A. Meredith Hughes'
- Brenda Matthews
- Kate Su
title: Resolved Millimeter Observations of the HR 8799 Debris Disk
---

Introduction {#sec:intro}
============

The young [30 Myr, @malo13] and nearby [39.4 pc, @van07] A-type star HR 8799 is the host of the first (and so far only) directly imaged multiple planet system. Near-infrared images show four companions with projected separations of 14, 24, 38, and 68 AU [@marois08; @marois10] whose orbital motions have been tracked over a decade [e.g. see the compilation by @bowler16]. Comparison of infrared photometry with standard (“hot-start”) evolutionary models suggest these companions have masses in the range of $5-10$ M$_{\rm Jup}$ [@marley12]. This inference is consistent with calculations that imply planet masses $<10$ M$_{\rm Jup}$ for dynamical stability at the age of the system, which also could be bolstered by a 1:2:4:8 mean motion resonance configuration [e.g. @gozdziewski14; @pueyo15; @maire15]. Analysis of self-consistent and homogeneous astrometric measurements indicate that the planet orbits have 