منابع مشابه
Infrared Spectrum and Abundances of the Planetary Nebula Ic 2448
We present the mid-infrared spectrum of the planetary nebula IC 2448. In order to determine the chemical composition of the nebula, we use the infrared line fluxes from the Spitzer spectrum along with optical line fluxes from the literature and ultraviolet line fluxes from archival IUE spectra. We determine an extinction of CHβ = 0.27 from hydrogen recombination lines and the radio to Hβ ratio....
متن کاملAstronomy & Astrophysics Abundances in the planetary nebula NGC 6210
The spectra of the planetary nebula NGC 6210 is reanalysed using spectral measurements made in the mid-infrared with the Spitzer Space Telescope and the Infrared Space Observatory. The aim is to determine the chemical composition of this object. We also make use of IUE and ground based spectra. Abundances determined from the mid-infrared lines, which are insensitive to electron temperature, are...
متن کاملPrecessing Collimated Outflows in the Planetary Nebula Ic 4846
We present [N ii] and Hα images and high resolution long–slit spectra of the planetary nebula IC4846, which reveal, for the first time, its complex structure and the existence of collimated outflows. The object consists of a moderately elongated shell, two (and probably three) pairs of collimated bipolar outflows at different orientations, and an attached circular shell. One of the collimated p...
متن کاملExpansion Parallax of the Planetary Nebula Ic 418
In this paper, we present radio continuum observations of the planetary nebula IC 418 obtained at two epochs separated by more than 20 years. These data allow us to show that the angular expansion rate of the ionization front in IC 418 is 5.8 ± 1.5 mas yr−1. If the expansion velocity of the ionization front is equal to the expansion velocity of the gas along the line of sight as measured by opt...
متن کاملa model for the dynamical and ionization structure of planetary nebula ic 418
the interacting two winds model and a spherical density distribution function are introduced to study the dynamical and ionization structure of the planetary nebula ic 418. a fast wind with a mechanical luminousity 2/34×1034erg.s-1 of interacts with a super wind with a mass-loss rate of 2×10-5m(°)yr-1 and a velocity of 10 , and produces a dense and luminous medium. in this model, the expan...
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ژورنال
عنوان ژورنال: The Astronomical Journal
سال: 2001
ISSN: 0004-6256
DOI: 10.1086/321171