Statistical study of extrasolar Kuiper belts with Herschel/DUNES

已知在原行星盘的内部，星子向行星的吸积效率更高。在它们的外围部分，盘的表面密度太低，或者行星的引力形成得更近，动态地加热盘，吸积在亚行星尺寸时停止，只产生微行星和矮行星的集合体。这些位于行星系统外围的小天体群被称为“太阳系外柯伊伯带”或碎片盘。虽然星子本身不能直接在其他恒星周围被探测到，但它们在连续的碰撞级联中产生的尘埃可以通过其热辐射被观测到。关于不可见行星和微行星的形成和演化的宝贵信息被印在这些尘埃碎片盘的观测统计数据中，并可以从中检索。这些统计数据反映了碎片盘未受扰动的碰撞演化阶段，以及行星向外迁移等扰动事件。在大量初步工作的基础上，我们建议利用赫歇尔空间天文台提供的新数据，通过碎片盘演变的具体模型和总体综合方法，对这些联系进行量化。通过这种方式，我们的目标是对行星系统的形成和演化情景设置新的约束。

Accretion of planetesimals to planets is known to be more efficient in inner parts of protoplanetary discs. In their outer parts, where the disc surface density is too low or gravity of planets formed closer-in dynamically heat the disc, accretion ceases at sub-planetary sizes and only yields ensembles of planetesimals and dwarf planets. These populations of small bodies on the periphery of the planetary systems are called “extrasolar Kuiper belts” or debris discs. While the planetesimals themselves cannot be directly detected around other stars, the dust that they produce in a continuous collisional cascade can be observed through its thermal emission. Valuable information about the formation and evolution of invisible planets and planetesimals is imprinted into the observational statistics of such dusty debris discs – and can be retrieved from it. These statistics reflect phases of unperturbed, collisional evolution of debris discs combined with perturbing events such as the outward migration of planets. Based on substantial preliminary work, we propose to quantify these links by means of specific models of debris disc evolution and the population synthesis method, making use of the new data coming from the Herschel Space Observatory. In this way, we aim at setting new constraints on formation and evolution scenarios of planetary systems.