ar X iv : a st ro - p h / 04 07 29 2 v 1 1 4 Ju l 2 00 4 Parameters of PNe : Old fashioned or Trendy ?
نویسنده
چکیده
We derive the stellar and circumstellar parameters with two models: the classical constant density nebula model and a stellar wind model. Depending on the mass loss rate of the star the stellar wind model results in a range of valid values which can deviate from the classical model results. This is especially true for the elemental abundances which are for every valid stellar wind model larger than the value found with the classical nebula model. We argue that a density distribution in the shells of PNe formed due to a stellar wind with high mass loss rate is more reliable when deriving stellar and nebular parameters than using the classical constant density nebula model.
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ar X iv : a st ro - p h / 04 07 23 2 v 1 1 2 Ju l 2 00 4 B The Saas Fee Lectures on Strong Gravitational Lensing
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