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

行星的形成机制和时间尺度仍然是未知的：行星可能是由直接的引力坍缩（快速）或由星周盘中的尘埃凝聚（缓慢）形成的。如果发现有行星的非常年轻的恒星，就可以得到时间尺度上的限制。项目的一部分是对几个年轻恒星样本的自适应光学成像（第一历元数据部分已经可用，ESO观测时间已被批准），年龄从1到600兆尔，即讨论中的行星形成时间尺度的全部范围。在另一部分，我们将用VLT/Sinfoni对年轻的次恒星伴星（棕矮星和/或行星）进行积分场光谱分析，与模型大气进行比较，以确定所有这些物体的温度和重力（也包括亮度和温度的半径），从而确定它们的质量。我们计划评估次恒星伴星是行星还是褐矮星的性质，并约束模型大气。然后，我们可以研究棕矮星和行星作为不同年龄的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.