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Formation of Close Giant Planets

近距离巨行星的形成

基本信息

批准号：
13640240
负责人：
NAKAGAWA Yoshitsugu
金额：
$ 2.24万
依托单位：
Kobe University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13640240/
关键词：
Extrasolar Planets Planetary Formation Origin of Solar System Jovian Planets Giant Planets 巨大惑星惑星集積

项目摘要

Formation of giant planets along the standard model of planetary formation is considered in the innermost region of protoplanetary disk nebulae where turbulence has already decayed. It is shown that if dust material enough to form a core with about ten times Earth mass and the corresponding amount of gas exist in the innermost region, a giant planet with mass somewhat larger than our Jupiter can form there.We also investigate the stability of planetary orbits around a binary stars, whose example is MACHO 97-BLG-41, an extrasolar planet detected in a binary system by gravitational microlensing. We performed long-term numerical integrations of the coplanar elliptic restricted three-body problem with various initial conditions in order to see what initial conditions produce stable planetary orbits during the integration for about three million years. The result of our numerical simulation permit us to estimate the upper limit of binary eccentricity, which ensures stable planetary orbital motion, to be about 0.5 in the cases of circular initial orbits of the planet. In the cases of elliptic initial orbits of the planet, the planetary orbital motion is found to be less stable; hence, the upper limit of the binary eccentricity is estimated to be smaller than that in the cases of circular initial orbits of the planet. The upper limit of the initial planetary eccentricity is estimated to be about 0.4 for stable planetary motion. The results of similar integrations for retrograde orbits indicate that the planetary retrograde orbits are more stable than the prograde ones.

巨行星的形成沿着行星形成的标准模型被认为是在原行星盘状星云的最内部区域，那里的湍流已经衰减。结果表明，如果尘埃物质足以形成一个质量约为地球10倍的核心，并且在最内层区域存在相应数量的气体，则可以在那里形成一颗质量比木星稍大的巨行星。我们还研究了双星系统中行星轨道的稳定性，并以微引力透镜观测到的太阳系外行星BSO 97-BLG-41为例进行了研究。我们进行了长期的数值积分的共面椭圆形限制性三体问题的各种初始条件，以了解什么样的初始条件下产生稳定的行星轨道在积分约300万年。我们的数值模拟的结果允许我们估计的二进制偏心率的上限，这确保稳定的行星轨道运动，在圆形的行星的初始轨道的情况下，约为0.5。在行星的椭圆初始轨道的情况下，行星的轨道运动被发现是不太稳定的，因此，估计的双偏心率的上限是小于在行星的圆形初始轨道的情况下。对于稳定的行星运动，初始行星偏心率的上限估计为约0.4。对逆行轨道的相似积分结果表明，行星逆行轨道比行星逆行轨道更稳定。