Terrestrial planet formation in low-eccentricity warm-Jupiter systems
Terrestrial planet formation in low-eccentricity warm-Jupiter systems
复制标题
DOI：
10.1051/0004-6361/200811305
复制
发表时间：
2009-01
影响因子：
6.5
通讯作者：
M. Fogg;R. Nelson
中科院分区：
文献类型：
--
作者：
M. Fogg;R. Nelson
背景。已发现太阳系外的巨行星围绕其宿主恒星运行的半长轴范围很广，0.02≤a≤6天文单位。当前的理论表明，在约0.02 - 2天文单位距离处运行的巨行星可能是在更远的距离形成的，并通过Ⅱ型迁移移动到它们当前的位置，在此过程中扰乱了任何正在形成的类地行星的内部系统。迁移可能由于气体盘适时的消散而停止。
目的。本文的目的是研究巨行星迁移对内部类地行星系统形成的影响。我们考虑巨行星由于气体盘消散而在0.13 - 1.7天文单位的半长轴处停止迁移的情况，并研究在形成的类地系统中考虑或忽略Ⅰ型迁移力的影响。
方法。我们使用一个与粘性气体盘算法相联系的N体代码，该算法能够模拟通过吸积到中心恒星和光致蒸发导致的气体损失、巨行星造成的间隙形成、巨行星的Ⅱ型迁移、原行星可选的Ⅰ型迁移以及对小行星的气体阻力。
结果。大多数内部系统的行星构建块在巨行星经过时得以幸存，要么被向内引导，要么被散射到外部轨道。预计会形成一个或多个热地球系统并保持在巨行星内部，特别是如果Ⅱ型迁移受到限制，或者Ⅰ型迁移影响了原行星动力学。如果巨行星对宜居带（HZ）的外部区域进行有限的侵入，或者穿过其整个宽度并在小于宜居带内边缘半径一半的距离处停止迁移，那么在低偏心率的热木星系统中出现宜居行星是可能的。
结论。Ⅱ型迁移不会阻止类地行星的形成。存在各种各样可能拥有宜居行星的行星系统结构。
Context. Extrasolar giant planets are found to orbit their host stars with a broad range of semi-major axes 0.02 ≤ a ≤ 6 AU. Current theories suggest that giant planets orbiting at distances between � 0.02−2 AU probably formed at larger distances and migrated to their current locations via type II migration, disturbing any inner system of forming terrestrial planets along the way. Migration probably halts because of fortuitously-timed gas disk dispersal. Aims. The aim of this paper is to examine the effect of giant planet migration on the formation of inner terrestrial planet systems. We consider situations in which the giant planet halts migration at semi-major axes in the range 0.13−1.7 AU due to gas disk dispersal, and examine the effect of including or neglecting type I migration forces on the forming terrestrial system. Methods. We employ an N-body code that is linked to a viscous gas disk algorithm capable of simulating gas loss via accretion onto the central star and photoevaporation, gap formation by the giant planet, type II migration of the giant, optional type I migration of protoplanets, and gas drag on planetesimals. Results. Most of the inner system planetary building blocks survive the passage of the giant planet, either by being shepherded inward or scattered into exterior orbits. Systems of one or more hot-Earths are predicted to form and remain interior to the giant planet, especially if type II migration has been limited, or where type I migration has affected protoplanetary dynamics. Habitable planets in low-eccentricity warm-Jupiter systems appear possible if the giant planet makes a limited incursion into the outer regions of the habitable zone (HZ), or traverses its entire width and ceases migrating at a radial distance of less than half that of the HZ’s inner edge. Conclusions. Type II migration does not prevent terrestrial planet formation. A wide variety of planetary system architectures exists that can potentially host habitable planets.