Modeling circumbinary planets: The case of Kepler-38
Modeling circumbinary planets: The case of Kepler-38
复制标题
DOI：
10.1051/0004-6361/201323235
复制
发表时间：
2014-01
影响因子：
6.5
通讯作者：
W. Kley;N. Haghighipour
中科院分区：
文献类型：
--
作者：
W. Kley;N. Haghighipour
上下文最近，开普勒太空望远镜发现了一些围绕双星运行的行星。在少数系统中，行星的位置接近动力学稳定极限。由于很难在如此近的轨道上形成行星，人们认为它们在更远的地方形成，并迁移到现在的位置。目标。我们的目标是建立更真实的模型，行星迁移在circumbinary磁盘和更准确地确定这些行星的最终位置。在我们的工作中，我们专注于开普勒-38系统，其中行星接近稳定极限。方法.利用二维流体动力学模拟研究了环双星盘的演化过程。我们研究局部等温磁盘以及更现实的模型，包括全粘性加热，从磁盘表面的辐射冷却，和辐射扩散的磁盘中平面。在圆盘进入准平衡状态后，嵌入一颗115地球质量的行星，并跟踪其演化。结果在所有的情况下，行星停止向内迁移靠近磁盘的内边缘。在具有典型盘尺度高度H / r = 0.05的等温盘中，最终结果与观测到的行星开普勒-38b的位置非常吻合。对于辐射模型，圆盘的厚度和内缘的位置由系统中的质量决定。对于表面密度为3000克/厘米2的顺序在1 Au，内间隙位于接近的二进制和行星停止在该区域之间的5：1和4：1的平均运动共振与二进制。一个圆盘的质量约为四分之一的模型产生的最终位置非常接近观测到的位置。结论.对于在环双星盘中迁移的行星，最终的位置取决于盘的结构。已知观测到的环联行星轨道，嵌入行星的辐射盘模拟可以提供系统演化最后阶段物理状态的重要信息。
Context. Recently, a number of planets orbiting binary stars have been discovered by the Kepler space telescope. In a few systems the planets reside close to the dynamical stability limit. Owing to the difficulty of forming planets in such close orbits, it is believed that they have formed farther out in the disk and migrated to their present locations. Aims. Our goal is to construct more realistic models of planet migration in circumbinary disks and to determine the final position of these planets more accurately. In our work, we focus on the system Kepler-38 where the planet is close to the stability limit. Methods. The evolution of the circumbinary disk is studied using two-dimensional hydrodynamical simulations. We study locally isothermal disks as well as more realistic models that include full viscous heating, radiative cooling from the disk surfaces, and radiative diffusion in the disk midplane. After the disk has been brought into a quasi-equilibrium state, a 115 Earth-mass planet is embedded and its evolution is followed. Results. In all cases the planets stop inward migration near the inner edge of the disk. In isothermal disks with a typical disk scale height of H / r = 0.05, the final outcome agrees very well with the observed location of planet Kepler-38b. For the radiative models, the disk thickness and location of the inner edge is determined by the mass in the system. For surface densities on the order of 3000 g/cm 2 at 1 AU, the inner gap lies close to the binary and planets stop in the region between the 5:1 and 4:1 mean-motion resonances with the binary. A model with a disk with approximately a quarter of the mass yields a final position very close to the observed one. Conclusions. For planets migrating in circumbinary disks, the final position is dictated by the structure of the disk. Knowing the observed orbits of circumbinary planets, radiative disk simulations with embedded planets can provide important information on the physical state of the system during the final stages of its evolution.