Cavity opening by a giant planet in a protoplanetary disc and effects on planetary migration
Cavity opening by a giant planet in a protoplanetary disc and effects on planetary migration
复制标题
原行星盘中巨行星的空腔开口及其对行星迁移的影响
DOI：
--
复制
发表时间：
2007
期刊：
影响因子：
--
通讯作者：
A. Morbidelli
中科院分区：
文献类型：
--
作者：
A. Crida;A. Morbidelli
我们研究了类木行星对原行星盘气体分布的影响，使用了一种新的数值方案，使我们能够考虑到圆盘的整体演化，直至任意小的内部物理半径。我们发现类木行星不会在盘的内部打开空腔（即在它们的轨道内部），除非(a)盘的内部物理边缘靠近行星的位置或(b)行星的质量比盘大得多。在所有其他情况下，行星只是在气体密度分布中打开了一个缺口，相对于没有行星的情况，其全球分布基本上没有变化。然而，我们认识到，尘埃的分布可能与气体的分布有很大的不同，在某些情况下，即使气体仍然存在于圆盘的内部，尘埃腔也可能被打开。关于行星的迁移，我们发现经典的II型迁移（速度与圆盘的粘度成正比）只有在行星打开的间隙深而干净的情况下才会发生。如果空隙中仍然有大量的气体，行星的迁移通常比理论的II型迁移速率慢。在某些情况下，迁移可以停止甚至逆转。我们开发了一个简单的模型，可以令人满意地再现模拟中观察到的迁移速率，适用于大范围的圆盘粘度、行星质量和相对于内圆盘边缘的位置。我们的结果与太阳系外行星系统相关，因为它们解释了(a)为什么一些热木星没有一直迁移到它们的母恒星上，(b)为什么一对共振行星的最外层通常是质量最大的一个。
We study the effect of a Jovian planet on the gas distribution of a protoplanetary disc, using a new numerical scheme that allows us to take into consideration the global evolution of the disc, down to an arbitrarily small inner physical radius. We find that Jovian planets do not open cavities in the inner part of the disc (i.e. interior to their orbits) unless (a) the inner physical edge of the disc is close to the planet’s location or (b) the planet is much more massive than the disc. In all other cases the planet simply opens a gap in the gas density distribution, whose global profile is essentially unchanged relative to the one that it would have if the planet were absent. We recognize, though, that the dust distribution can be significantly different from the gas distribution and that dust cavities might be opened in some situations, even if the gas is still present in the inner part of the disc. Concerning the migration of the planet, we find that classical type II migration (with speed proportional to the viscosity of the disc) occurs only if the gap opened by the planet is deep and clean. If there is still a significant amount of gas in the gap, the migration of the planet is generally slower than the theoretical type II migration rate. In some situations, migration can be stopped or even reversed. We develop a simple model that reproduces satisfactorily the migration rate observed in the simulations, for a wide range of disc viscosities and planet masses and locations relative to the inner disc edge. Our results are relevant for extrasolar planetary systems, as they explain (a) why some hot Jupiters did not migrate all the way down to their parent stars and (b) why the outermost of a pair of resonant planets is typically the most massive one.