THE DEBRIS DISK AROUND HR 8799

Abstract

We have obtained a full suite of Spitzer observations to characterize the\ndebris disk around HR 8799 and to explore how its properties are related to the\nrecently discovered set of three massive planets orbiting the star. We\ndistinguish three components to the debris system: (1) warm dust (T ~150 K)\norbiting within the innermost planet; (2) a broad zone of cold dust (T ~45 K)\nwith a sharp inner edge, orbiting just outside the outermost planet and\npresumably sculpted by it; and (3) a dramatic halo of small grains originating\nin the cold dust component. The high level of dynamical activity implied by\nthis halo may arise due to enhanced gravitational stirring by the massive\nplanets. The relatively young age of HR 8799 places it in an important early\nstage of development and may provide some help in understanding the interaction\nof planets and planetary debris, an important process in the evolution of our\nown solar system.\n