Planetary nebula are useful kinematic tracers of the stars in all galaxy types. I review recent observationally-driven developments in the study of galaxy mass profiles. These have yielded surprising results on spiral galaxy disk masses and elliptical galaxy halo masses. A key remaining question is the coupling between PNe and the underlying stellar populations.

The fact that Space Telescope WFPC2 images of the planetary nebula NGC 6537 fail to show the central star is used to derive a limit to its magnitude: it is fainter than a magnitude of 22.4 in the visible. This is used to derive a lower limit to the temperature of the star. The Zanstra temperature is at least 500 000 K. The Energy Balance temperature is found to be consistent with this value, as...

Eleven objects that have been reported as proto-planetary nebula or as young planetary nebulae that show very extended Hα wings are presented. The extension of these wings is larger than 800 km s . Data for two symbiotic stars that show this same characteristic is also presented. Raman scattering is the mechanism that best explains the wings in 10 of the PNe and in the 2 symbiotic stars. In the...

Planetary materials contain an abundance of 3d transition metals. They occur in mineral phases that formed in a wide range of environments, e.g., the gaseous envelopes surrounding ancient stars and the early solar nebula. The ability of such metals to occur in multiple oxidation states makes them potentially useful recorders of the redox conditions under which their host assemblage formed or la...

Introduction: Sr model ages provide constraints on early solar system chronology. The timing and duration of condensation events from the solar nebula, and of subsequent differentiation of planetary bodies are of particular interest. Model age uncertainty depends partly on the precision in the initial solar system 87 Sr/ 86 Sr ratio. Here we measure

We present 2D hydrodynamical simulations of the transition a proto-planetary nebula to planetary for central stars in binary systems that have undergone common envelope event. After 1,000 yr magnetically driven dynamics (proto-planetary phase), line-driven stellar wind is introduced into computational domain and expansion simulated another 10,000 yr, including effects photoionization. In this s...

We have combined two epochs of Hubble Space Telescope WFPC2 imaging data with ground-based expansion velocities to determine distances to three planetary nebulae (NGC 6578, NGC 6884, and IC 2448). We used two variants of the expansion parallax technique—a gradient method and a magnification method— to determine the distances. The results from the two methods agree to within the errors. A fourth...

In recent decades, a number of molecules and diverse dust features have been identified by astronomical observations in various environments. Most of the dust that determines the physical and chemical characteristics of the interstellar medium is formed in the outflows of asymptotic giant branch stars and is further processed when these objects become planetary nebulae. We studied the environme...