标题： 无粘性盘中低质量行星的迁移：辐射传输对动力学共转扭矩的影响 显示英文标题

标题： Migration of low-mass planets in inviscid disks: the effect of radiation transport on the dynamical corotation torque

摘要： 低质量行星在类型-I范围内迁移。 在无粘性极限下，行星共转区域内部的涡度与背景盘涡度之间的对比导致了动态共转力矩，据认为这会减缓向内迁移。 我们使用无粘性二维流体动力学模拟研究了辐射冷却对低质量行星迁移的影响。 我们发现冷却会在靠近行星的物质U型转弯处产生热力强迫，导致共转区域内的涡度增加，这反过来会削弱动态共转力矩，并导致2-3倍更快的向内迁移。 当冷却作用时间尺度与共转区域内物质的U型转弯时间尺度相似时，这一机制最有效，但在典型的盘中（5-50天文单位），它仍然适用于相当大的径向范围。 随着行星向内迁移，共转区域内外的涡度对比增加，并部分调节热力强迫的效果。 作为次要效应，我们表明辐射阻尼可以进一步削弱由行星螺旋激波产生的涡度屏障，从而支持向内迁移。 最后，我们强调，与局部冷却相比，自洽地处理辐射扩散是至关重要的，以避免高估涡度增长和由此产生的迁移率。 显示英文摘要

摘要： Low-mass planets migrate in the type-I regime. In the inviscid limit, the contrast between the vortensity trapped inside the planet's corotating region and the background disk vortensity leads to a dynamical corotation torque, which is thought to slow down inward migration. We investigate the effect of radiative cooling on low-mass planet migration using inviscid 2D hydrodynamical simulations. We find that cooling induces a baroclinic forcing on material U-turning near the planet, resulting in vortensity growth in the corotating region, which in turn weakens the dynamical corotation torque and leads to 2-3x faster inward migration. This mechanism is most efficient when cooling acts on a timescale similar to the U-turn time of material inside the corotating region, but is nonetheless relevant for a substantial radial range in a typical disk (5-50 au). As the planet migrates inwards, the contrast between the vortensity inside and outside the corotating region increases and partially regulates the effect of baroclinic forcing. As a secondary effect, we show that radiative damping can further weaken the vortensity barrier created by the planet's spiral shocks, supporting inward migration. Finally, we highlight that a self-consistent treatment of radiative diffusion as opposed to local cooling is critical in order to avoid overestimating the vortensity growth and the resulting migration rate.