Probing the dust population of debris disks with HST
Debris disks are dynamical laboratories that can tell us both about the presence of planets and the dynamical processes at work in extrasolar systems. They are formed of planetesimals left over from planet formation and constantly produce dust particles through a collisional cascade. Studying the dust spatial and size distribution can inform us about interactions with unseen nearby planets and about the dynamical balance in the system. In particular, imaging these systems in the visible and near-infrared directly addresses these questions by letting us observe their morphology at high angular resolution and analyze their scattering properties, directly influenced by the micron-size grains in the system.
Through our consistent reanalysis of archival near-infrared HST images (the ALICE program), we recently imaged 11 debris disks for the first time in scattered light. All these disks have relatively low surface brightnesses indicating different dust populations compared to several well-characterized bright systems. I will present the ALICE program, these disk detections, and prospects to further characterize their dust population.