A Cat's Eye view of the Eskimo from Saturn

Abstract

The 3-D and kinematic structure of the Eskimo nebula, NGC 2392, has been notoriously difficult to interpret given its complex morphology, multiple kinematic components and its nearly pole-on orientation along the line of sight. Here we present the most comprehensive high resolution spectroscopic mapping of the Eskimo planetary nebula to date. The data consist of 21 spatially resolved, long-slit echelle spectra tightly spaced over the Eskimo and along its bipolar jets. This data set allowed us to construct a velocity-resolved [NII] channel map of the nebula with a resolution of 10 km/s that disentagles the differente kinematic components of the nebula and reveals clearly for the first time the kinematic expansion pattern for each of the components. The spectroscopic information is combined with a HST image to construct the first detailed three dimensional model of the Eskimo with the code SHAPE. With this model we demostrate that the Eskimo is nearly a twin to the Saturn nebula, but rotated 90° to the line sight. Furthermore, we show that the main characteristics of our model apply to the general properties of the group of elliptical planetary nebulae with ansae, once the orientation is considered.