Cold debris disks around nearby stars

行星系统有多常见这一问题对天体物理学来说至关重要。赫歇尔空间观测站的关键项目“附近恒星周围的尘埃”(沙丘)将解决年轻恒星周围的行星/行星系统在盘中形成的普遍性问题。这是一个对微弱、寒冷的碎片盘进行系统搜索的计划，目的是寻找太阳附近小行星系统的入射分数。更具体地说，沙丘是一项灵敏度和体积有限的(d&lt；25PC)调查，对133颗年龄约0.1到~10 Gyr、光谱类型为F、G和K的恒星进行调查。拟议项目的目标是执行沙丘观测分析的中心部分。核心任务是模拟沙丘目标的热再发射，并尽可能模拟额外的观测数据(例如，多波长图像、偏振测量)，以便限制圆盘结构和尘埃特性。通过与沙丘联盟内的其他团队合作，这一模拟将能够得出关于小行星的形成依赖于恒星质量、小行星带的碰撞和动力学演化以及尘埃盘的存在和行星的存在之间可能的关联的结论。

The question of how common planetary systems are is of fundamental importance for astrophysics. The Herschel Space Observatory key program “Dust around nearby stars” (DUNES) will address the question about the universality of planets/planetary systems formation in disks around young stars. It is a systematic search program for faint, cold debris disks to find the fractional incidence of planetesimal systems in the solar neighbourhood. More specifically, DUNES is a sensitivity- and volume-limited (d < 25 pc) survey of 133 stars of age ~ 0.1 to ~ 10 Gyr and spectral types F, G, and K.The goal of the proposed project is to perform a central part of the analysis of the DUNES observations. The core task is to model the thermal reemission of the DUNES targets and – as far as available – additional observables (e.g., multi-wavelength images, polarization measurements) in order to constrain the disk structure and dust properties. In collaboration with the other teams within the DUNES consortium this modeling will allow to derive conclusions about the dependence of the planetesimal formation on the stellar mass, the collisional and dynamical evolution of planetesimal belts and possible correlations between the existence of dust disks and the presence of planets.