Evolution of eccentricity and inclination of hot protoplanets embedded in radiative discs
Evolution of eccentricity and inclination of hot protoplanets embedded in radiative discs
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嵌入辐射盘中的热原行星的偏心率和倾角的演化
DOI：
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
F. Masset
中科院分区：
文献类型：
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作者：
H. Eklund;F. Masset
本文利用三维流体力学计算方法，研究了嵌入在原行星盘中的原行星胚和低质量原行星（从地球质量的一小部分到几个地球质量）的偏心率和倾斜度的演化。当原行星在周围的圆盘中辐射由固体吸积释放的能量时，它们的偏心率和倾斜度会随着行星的光度与质量比而增长，这个值与圆盘的纵横比相当，并且在几千年的时间尺度上达到。这种增长是由行星附近出现的一个热的、低密度的区域引发的。离心率的增长率通常是倾斜度增长率的三倍。在长期的计算中，我们发现偏心的激励和倾斜的激励并不是相互独立的。在特殊情况下，一颗行星最初的离心率和倾斜度很小，离心率就会大大超过倾斜度。当偏心距达到渐近值时，倾角的增长被抑制，形成一个倾角很小的偏心轨道。作为附带结果，我们发现不发光行星的偏心率和倾角在辐射盘中比在等温盘中受到更强烈的阻尼。
We study the evolution of the eccentricity and inclination of protoplanetary embryos and low-mass protoplanets (from a fraction of an Earth mass to a few Earth masses) embedded in a protoplanetary disc, by means of three dimensional hydrodynamics calculations with radiative transfer in the diffusion limit. When the protoplanets radiate in the surrounding disc the energy released by the accretion of solids, their eccentricity and inclination experience a growth toward values which depend on the luminosity to mass ratio of the planet, which are comparable to the disc's aspect ratio and which are reached over timescales of a few thousand years. This growth is triggered by the appearance of a hot, under-dense region in the vicinity of the planet. The growth rate of the eccentricity is typically three times larger than that of the inclination. In long term calculations, we find that the excitation of eccentricity and the excitation of inclination are not independent. In the particular case in which a planet has initially a very small eccentricity and inclination, the eccentricity largely overruns the inclination. When the eccentricity reaches its asymptotic value, the growth of inclination is quenched, yielding an eccentric orbit with a very low inclination. As a side result, we find that the eccentricity and inclination of non-luminous planets are damped more vigorously in radiative discs than in isothermal discs.