Direct detection of sub-stellar companions around young stars and integral-field infrared spectroscopy

行星的形成机制及其时间尺度仍然未知：行星可能是通过引力直接塌缩(快速)或由星盘周围的尘埃凝聚形成(缓慢)。如果发现具有行星的非常年轻的恒星，就可以获得时间尺度上的约束。一个项目部分是对几颗年轻恒星的自适应光学成像(已经有部分第一纪元数据，给予ESO观测时间)，年龄从1到600 Myr，即正在讨论的行星形成时间的全部范围。在另一部分中，我们将使用VLT/Sinfoni对年轻的亚恒星同伴(棕矮星和/或行星)进行积分场光谱分析，并将其与模型大气进行比较，以确定所有这些天体的温度和重力(也包括光度和温度的半径)，从而确定它们的质量。我们计划评估亚恒星伴星的性质，如行星或棕矮星，并限制模型大气。然后我们就可以研究棕矮星和行星作为不同年龄段恒星的伴星的频率及其时间演化。

The planet formation mechanism and its time-scale are still unknown: Planets may form by direct gravitational collapse (fast) or by coagulation from dust in circumstellar disks (slow). Constrains on the time-scale can be obtained, if very young stars with planets are found. One project part is Adaptive Optics imaging of several samples of young stars (1st epoch data are partly already available, ESO observing time is granted) with ages from 1 to 600 Myrs, i.e. the full range of planet formation timescales under discussion. In another part, we will perform integral-field spectroscopy of young sub-stellar companions (brown dwarfs and/or planets) with VLT/Sinfoni - to be compared to model atmospheres to determine temperature and gravities of all those objects (also radii from luminosity and temperature), hence their masses. We plan to assess the nature of sub-stellar companions as being planets or brown dwarfs and to constrain model atmospheres. We can then study the frequency of brown dwarfs and planets as companions to stars of different age bins and its temporal evolution.