Wednesday, September 13, 2017

Effects of the Planetary Temperature on the Circumplanetary Disk and on the Gap

Effects of the Planetary Temperature on the Circumplanetary Disk and on the Gap




Circumplanetary disks regulate the late accretion to the giant planet and serve as the birthplace for satellites. Understanding their characteristics via simulations also helps to prepare for their observations. Here we study disks around 1, 3, 5, 10 MJup planets with three dimensional, global radiative hydrodynamic simulations with sub-planet peak resolution, and various planetary temperatures. We found that as the 1 MJup planet radiates away its formation heat, the circumplanetary envelope transitions to a disk between Tp=6000 K and 4000 K. In the case of 3-10 MJup planets a disk always forms. The temperature profile of the circumplanetary disks is very steep, the inner 1/6th is over the silicate condensation temperature and the entire disk is above water freezing point, making satellite formation impossible in this early stage (less than 1 Myr). Satellites might form much later and first in the outer parts of the disk migrating inwards later on. Our disk masses are 1,7,20,40×10−3MJup for the 1, 3, 5, 10 MJup gas giants respectively, and we provide an empirical formula to estimate the subdisk masses based on the planet- and circumstellar disk mass. Our finding is that the cooler the planet, the lower the temperature of the subdisk, the higher the vertical influx velocities, and the planetary gap is both deeper and wider. We also show that the gaps in 2D and 3D are different. The subdisk eccentricity increases with planetary mass and violently interacts with the circumstellar disk, making satellite-formation less likely, if Mp≳5MJup.

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