The formation zone of Jupiter-like planets - full young planetary systems

到目前为止，已经发现了300多颗太阳系外行星，其中大部分是通过径向速度技术，一些也是通过其他技术，如过境，天体测量和直接成像。由于灵敏度偏差，这些行星和它们的主星之间的距离通常在50 Au（直接成像检测）之外或在几个Au（其他技术）之内。这些行星的质量介于10个地球质量（像海王星这样的行星）和13个木星质量（可能是行星质量的上限）之间。在这个项目中，我们计划研究一个精心挑选的年轻恒星样本（星团25 Ori，10 Myrs），通过使用上述各种技术搜索类木星行星，以便我们可以找到给定质量范围内的所有行星（完整的质量可以达到木星质量的一半，但有些行星可能达到海王星质量），也就是说，我们可以找到整个行星系统。考虑到这些行星还很年轻，它们仍然靠近它们形成的位置（和分离）。通过直接成像，探测到几颗位于50 Au以外的行星（或候选行星）。目前尚不清楚行星是否能在离星星如此遥远的地方形成，那里的盘密度较低。在项目的第二部分，我们将通过跟踪自引力原行星吸积盘的演化，特别是外部分离极限，从理论上研究可能形成行星的分离范围。从给定的初始径向质量分布出发，我们将研究原行星吸积盘随时间的演化。特别地，我们感兴趣的是这些盘的外径的演化。在这种情况下，不仅（实际上）消失的质量密度的半径是相关的。当谈到行星的形成时，人们可能会想到其他类型的行星。（有效）外半径，如（垂直）自引力，超过它引力不稳定性不再可能，或半径，其中物质的径向速度从较小半径处的向内运动变为较大半径处的向外运动，超过该值，基本上只需要该材料来消除角动量。

More than 300 extra-solar planets have been discovered so far, most by the radial velocity technique, some also by other techniques like transit, astrometry, and direct imaging. The separations between those planets and their host stars are typically either outside of 50 AU (direct imaging detections) or within a few AU (other techniques) due to sensitivity biases. The planet masses are between about 10 Earth masses (planets like Neptune) and roughly 13 Jupiter masses (possibly upper planet mass limit). In this project, we plan to study one carefully selected sample of young stars (cluster 25 Ori, 10 Myrs) by searching for Jupiter-like planets with the various techniques mentioned above, so that we can find all planets in a given mass range (to be complete down to half a Jupiter mass, but some planets down to Neptune mass possible) for all possible separations, i.e. we can find whole planetary sys-tems. Given that those planets are young, they are still close to the location (and separa- tion), where they formed. By direct imaging, several planets (or planet candidates) were de-tected located outside of 50 AU. It is not clear whether planets can form so far away from the star, where the disk density is low.In the second part of the project, we will investigate the separation range of possible planet formation theoretically by following the evolution of selfgravitating protoplanetary accretion disks, in particular the outer separation limit. Starting from given initial radial mass distribu-tions, we will follow the time dependent evolution of protoplanetary accretion disks. In par-ticular, we are interested in the evolution of the outer radius of these disks. In this context, not only the radius of (virtually) vanishing mass density is of relevance. When talking about planet formation, one may think of additional types of (effective) outer radii, like the outer-most radius of (vertical) selfgravity, beyond which gravitational instability is no longer possi-ble, or the radius, where the radial velocity of the material changes sign from inward motion at smaller radii to outwards motion at larger radii, beyond which the material is needed bas-ically for getting rid of the angular momentum only.