WAVE EXCITATION IN ISOTHERMAL DISKS BY EXTERNAL GRAVITY

Wave excitation in isothermal disks with finite thickness by external gravity is investigated. The main application of this study is to clar ify the process of angular-momentum transfer in a protoplanetary disk by a protoplanet. It is found that waves with vertical motion (SD-wave s) as well as waves without vertical motion (2D-waves) are excited, an d that both waves can transfer angular-momentum. The 2D-waves have pro perties similar to the waves in infinitesimally thin disks. A protopla net on the central plane of the disk excites mainly 2D-waves. On the o ther hand, SD-waves have a minor effect on the angular-momentum transf er.