Direct detection of Jovian planets around young solar analogs and their atmospheres

目前还不清楚我们的太阳系与其他行星系统相比有多频繁和典型。径向速度搜索主要是针对类似太阳的早期G型恒星进行的，但几乎只观察到正常的主序星，并且只观察到近距离的大质量行星（最多几个Au，比几个地球质量多）可以通过径向速度搜索来探测。在这个新项目中，我们计划搜索大质量行星（大约是木星质量的一半或更多）围绕着年轻的恒星（高达1000万年），一旦它们在主序星上，它们将成为太阳的类似恒星。通过自适应光学和大型望远镜的直接成像，我们可以找到大约10个Au以上的所有大质量行星。一旦确认行星候选者是共同运动和绕星星运行，我们将在红外线中拍摄它们的大气光谱。然后，我们将这些光谱与模型大气，如最新的DRIFT-PHOENIX网格（Witte，Helling & Hauschildt）进行比较，以确定物理参数，如金属丰度，重力，温度，半径，因此，质量。除了寻找和观察年轻恒星周围的行星，我们还计划改进模型大气。质量估计的最关键参数是重力。因此，必须改进模型大气，以便从整体（准）连续体形状和单个重力敏感线精确确定重力变得可行。为此，必须考虑到更好的（剖面）线数据，再加上尘埃云的形成。此外，模型网格中覆盖的参数空间必须扩大（以包括质量较小，因此较冷的行星），网格计算具有更高的参数分辨率内的系统误差的最佳参数determination.We可以使用样本的年轻的大质量行星周围的年轻的太阳类似的恒星来研究我们的太阳系是多么典型，并限制其形成的情况。该项目是观测者和理论家之间的密切合作，也应该建立太阳系外行星和太阳系行星之间的密切联系。

It is not yet clear how frequent and typical our solar system is compared to other planetary systems. Radial velocity searches have been carried out mostly for solar-like early G-type stars, but almost only normal main sequence stars were observed and only close-in massive planets (up to few AU, more than a few Earth masses) can be detected by radial velocity searches.In this new project, we plan to search for massive planets (about half a Jupiter mass and more) around young stars (up to 10 Myrs), which will become solar analog stars once they are on the main sequence. By direct imaging with Adaptive Optics and large telescopes, we can find all massive planets upside of about ~ 10 AU.Once planet candidates are confirmed to be co-moving and orbiting the star, we will take spectra of their atmospheres in the infrared. We will then compare those spectra with model atmospheres such as most recent DRIFT-PHOENIX grid (Witte, Helling & Hauschildt) in order to determine physical parameters such as metallicity, gravity, temperature, radius and, hence, mass.In addition to the search and observation of planets around young stars, we also plan to improve the model atmospheres. The most critical parameter for mass estimation is the gravity. Hence, the model atmospheres have to be improved, so that the precise determination of gravities from both the overall (quasi-) continuum shape and the individual gravity-sensitive lines becomes feasible. For doing so, much better (profile) line data have to be taken into account, coupled to the formation of dust clouds. Also, the parameter space covered in the model grids has to be enlarged (to include less massive and thus cooler planets) and the grid has to be computed with higher parameter resolution for an optimum parameter determination inside the systematic errors.We can use the sample of young massive planets around young solar analog stars to investigate how typical our solar system is and to constrain its formation scenario. This project is a close collaboration between observers and theorists and should also establish a close link between extra-solar planets and solar system planets.