2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/341We report NICMOS wide-band and polarimetric observations of four proto-planetary nebulae. Molecular hydrogen emission is detected near the ends of the bipolar lobes of IRAS 17150-3224, which is evidence for the interaction of a fast, collimated outflow with the remnant of the asymptotic giant branch wind.To appear in ``Asymmetrical Planetary Nebulae II: from Origins to Microstructures,'' ASP Conference Series, Vol. 199, 2000; J.H. Kastner, N. Soker, & S.A. Rappaport, edsAstrophysicstext