Radiative forces on dust particles in circumstellar disks

当恒星周围的尘埃颗粒变得非常薄时，辐射力就会影响它们的动力学。辐射压力一直被认为是这样一种力，然而，目前的圆盘模型通过将尘埃颗粒近似为球体来实现这种力。虽然关于非球形粒子辐射压力的理论工作不多，但缺乏真实形状和尺寸的粒子辐射压力的实验数据。在这种情况下，人们对感光效应的了解就更差了。感光效应是指周围气体分子对被照射粒子施加的一种力。该项目的目的是获得关于不同大小、形状和组成的不规则形状尘埃颗粒上的辐射压力和光生动力的实验数据。应用先前开发的单粒子辐射压力测量装置，可以研究入射波长和粒子取向的依赖关系，并量化横向力分量。通过使用准静电粒子陷阱的新装置的单粒子测量，将研究光电性对星盘中尘埃的径向迁移、尘环的形成以及在盘外部区域形成的天体的组成的作用。

Radiative forces influence the dynamics of dust particles in circumstellar disks as soon as they become optically thin. Radiation pressure has long been recognized as such a force, however, current disk models implement this force by approximating the dust grains as spheres. While there are a few theoretical works on radiation pressure on non-spherical particles, experimental data of the radiation pressure force on particles with realistic shapes and sizes are missing. The knowledge of the effect of photophoresis, a force exerted on illuminated particles by surrounding gas molecules, is even poorer in this context. The aim of this project is to gain experimental data on the radiation pressure and photophoretic forces on irregularly shaped dust particles of various sizes, forms, and compositions. The application of a previously developed setup for radiation pressure measurements with single particles allows for studying the dependence on the incident wavelength and the particle orientation, and for quantifying the transverse force component. The role of photophoresis for the radial migration of dust in circumstellar disks, the formation of dust rings, and the composition of bodies formed in the outer regions of the disk will be investigated by single particle measurements with a new setup using a quasi-electrostatic particle trap.