2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/12914We consider several processes operating during the late stages of planet formation that can affect observed orbital elements. Disk-planet interactions, tidal interactions with the central star, long term orbital instability and the Kozai mechanism are discussed.26 pages, TeX, 3 figures (2 in color), 2 style files (ppiv-style.tex and epsf.sty), to be published in "Protostars and Planets IV," eds. A. Boss, V. Mannings, and S. RussellAstrophysicstext