Estudos de variação espacial de abundâncias: o caso da nebulosa planetária Menzel 1

Abstract

Planetary Nebulae (PNe) are objects of very complex morphologies and the details of their spatial structure formation are still object of investigation. There are few works that take into account the three-dimensional character of objects. In addition to the spherical structure, the older models also assume that the abundance of elements is uniform throughout the PNe. Just few studies explore the hypothesis that there are variations in abundances. In this work, we present a model for the planetary nebula Menzel 1 made with the code MOCASSIN. Its bipolar structure and homogeneous abundances were taken into account in order to analyze how they can influence the results obtained. We show that the results obtained with the updated model lead to significantly different values when compared to previous models for the same object. We discuss the influence of atomic data and the detailed treatment of diffuse radiation on the discrepancies found. With the NEAT code, integrated and bidimensional abundances were determined from the flux maps derived from the model. The abundance maps show discrepancies with respect to the initial parameters of the model. We conclude that the empirical method creates non-real variations since this method does not take into account the three-dimensional complexity of the object’s structure.