Institute of Astronomy

Photophoresis effects in Protoplanetary Disks: a numerical approach

SpeakerTalk DateTalk Series
Nicolas Cuello28 July 2014Across HR 2014 Posters


It is thought that planets form in the inner regions of protoplanetary disks (PPD) about 1-10 AU. However, the migration of solids, in some cases sending them in a very short time onto the star, is a problem for planet formation, known as the radial-drift barrier. It is crucial to overcome this major difficulty in order to build up planet cores next to the star. Several effects have been proposed to invert the radial drift of the planetesimals (magnetic breaking, dead-zones, meridional flow, turbulence, particle traps, etc...). In this work, we explore the star radiation effect on the inner regions of PPD, namely photophoresis. It is a very promising phenomenon which has been poorly explored from the numerical point of view. Based on recent experiments of Duermann, Wurm and Kuepper, photophoresis (i.e. the thermal creep induced by the star irradiation) seems a good candidate. Indeed, they showed that its effects could revert the inward motion of meter-sized planetesimals at 1 AU in the disk. By means of a semi-analytical model, it can be shown that this force depends on the total size of the grain and on its porosity. We include this effect in our two-fluid (gas+dust) SPH code in order to explore whether or not this effect can break the radial-drift barrier. We run a series of numerical simulations for various disk configurations and grain sizes to assess its impacts on dynamics and growth.