2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/4991The 2:1 orbital resonances of the GJ 876 system can be easily established by the differential planet migration due to planet-nebula interaction. Significant eccentricity damping is required to produce the observed orbital eccentricities. The geometry of the GJ 876 resonance configuration differs from that of the Io-Europa pair, and this difference is due to the magnitudes of the eccentricities involved. We show that a large variation in the configuration of 2:1 and 3:1 resonances and, in particular, asymmetric librations can be expected among future discoveries.4 pages, including 4 figures; uses newpasp.sty; to appear in Scientific Frontiers in Research on Extrasolar Planets (ASP Conf. Series)Astrophysicstext