low eccentricity and are consistent with coplanarity [@konopacky16]. These relatively bright and wide-separation super-Jovian planets are also a favorite target for spectroscopic observations aimed at planetary atmosphere characterization [@barman11; @konopacky13; @ingraham14; @barman15; @bonnefoy16; @zurlo16].

The HR 8799 system hosts, in addition to planetary mass companions, a dusty debris disk that was first detected by [*IRAS*]{} [@sadakane86]. The debris disk has been investigated in detail at wavelengths from $24-850~\mu$m using observations from [*Spitzer*]{} [@su09], [*Herschel*]{} [@matthews14], and the JCMT [@williams06; @holland17]. These multi-wavelength observations show that the debris consists of a warm (T$\sim150$ K) inner belt and a cold (T$\sim35$ K) outer belt that bracket the orbits of the directly imaged planets, plus an extended halo of small grains that is detected out to radii beyond $1000$ AU. The 850 $\mu$m photometry marks the HR 8799 debris disk as one of the most massive known, at an estimated mass of $\sim0.1$ M$_{\rm Earth}$. Modeling of resolved far-infrared images suggests the presence of a population of colliding planetesimals underlying the cold belt that extends from about $100$ to $300$ AU, albeit with significant uncertainty on the locations of these boundaries on account of insufficient angular resolution for the inner edge and confusion 