Metal Absorption Profiles from the Central Star of the Planetary Nebula M27 (NGC 6853, PN G060.8-03.6, the Dumbbell) -- Photospheric and Nebular Line Identifications

Abstract

High resolution spectra of the hot central star of the planetary nebula (CSPN) M27, acquired with the Far Ultraviolet Spectroscopic Explorer (\FUSE), have revealed an unusually rich set of narrow molecular hydrogen absorption features. This object is also unique in that the velocity of nebular absorption features are cleanly separated from the velocity of the intervening interstellar medium. These features blend with and in many cases obscure atomic features. We have developed a continuum model of the CSPN including atomic and molecular hydrogen absorption. Using this model we have identified and tabulated the metal lines as arising from either photospheric, nebular and/or non-nebular velocity systems. We find the nebular outflow and ionization balance to be stratified with high ionization states favored at low velocity and low ionization states favored at high velocity. Neutrals and molecules are found at a velocity that marks the transistion between these two regimes. These observations are a challenge to the interacting wind model of PN evolution. Mappings at high resolution of the line profiles for \ion{C}{1} \ion{-}{4}, \ion{N}{1} \ion{-}{3}, \ion{O}{1}, \ion{O}{6}, \ion{Si}{2} \ion{-}{4}, \ion{P}{2} \ion{-}{5}, \ion{S}{2} \ion{-}{4}, \ion{Ar}{1} \ion{-}{2} and \ion{Fe}{2} \ion{-}{3} within the \FUSE and STIS bandpasses are presented. The digitial spectra of the stars and the model are freely available on the H${}_2$ools website. They will be useful for photospheric analyses seeking to determine the metallicity of the central star and for absorption line based atomic and molecular abundance determination of the nebular outflow.

arXiv commentCorrected wrong alternate designations for M27 in the title. Now in emlateapj 2 column, 25 pages total, 16 figures. Accepted for ApJS on 14 Dec 2006

References in corpus (10)

• Overview of the Far Ultraviolet Spectroscopic Explorer Mission
• On-Orbit Performance of the Far Ultraviolet Spectroscopic Explorer (FUSE) Satellite
• A grid of synthetic ionizing spectra for very hot compact stars from NLTE model atmospheres
• The Dynamical Evolution of the Circumstellar Gas around Low- and Intermediate-Mass stars.II. The Planetary Nebula formation
• Molecular Hydrogen Optical Depth Templates for FUSE Data Analysis
• The creation of the Helix planetary nebula (NGC 7293) by multiple events
• High-resolution ultraviolet spectroscopy of PG1159-035 with HST and FUSE
• Astrometry with Hubble Space Telescope: A Parallax of the Central Star of the Planetary Nebula NGC 6853
• Discovery of Lyman-alpha Pumped Molecular Hydrogen Emission in the Planetary Nebulae NGC 6853 and NGC 3132
• Molecular and Atomic Excitation Stratification in the Outflow of the Planetary Nebula M27

Cited by in corpus (1)

• Optical line profiles of the Helix planetary nebula (NGC 7293) to large radii