Spatially resolved planetary nebulae: characterizing (micro) structures of low-ionization

• Grant number: 04/11837-0
• Support Opportunities: Scholarships in Brazil - Young Researchers
• Start date: November 01, 2004
• End date: April 30, 2007
• Field of knowledge: Physical Sciences and Mathematics - Astronomy - Astrophysics of the Interstellar Medium
• Principal Investigator: Denise Rocha Gonçalves
• Grantee: Denise Rocha Gonçalves
• Host Institution: Instituto de Astronomia, Geofísica e Ciências Atmosféricas (IAG). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

In addition to their large-scale structures, mainly identified in the forbidden [Olll] emission line, many planetary nebulae have a number of small-scale structures which are instead more prominent in low-ionization lines (mainly [NII]), the low-ionization structures (LIS). LIS appear with a variety of morphologies: knots, tails, filaments, jets and jet-like structures of low ionization, in opposite pairs or as isolated features, attached to, or detached from, the main shells of the nebulae. They move with supersonic velocities through the large-scale components in which they are located, or instead as structures with the above morphologies but with low velocities that do not differ substantially from that of the main nebula. Thanks to the high spatial resolution of many telescopes/instruments now available, the inclusion of these kinds of structures in theoretical studies aimed at understanding the evolution of Sun-like stars, as well as the formation and evolution of PNe and their interplay with the interstellar medium (ISM), is mandatory. The main goal of the present project is to characterize LIS in terms of observations and theoretical modelling. Here, we aim at studying their physical, chemical and excitation properties (with optical and infrared data), mainly using Brazilian observational facilities, such as SOAR and GEMINI. The theoretical modelling will be developed with the photoionization codes, ionization correction factor codes, etc, developed by Brazilian researchers (W. Maciel, S. Viegas, R. Gruenwald, V. Jatenco-Pereira and D. Falceta-Gonçalves) and other collaborators from abroad (M. Perinotto, B. Ercolano and E. Villaver). (AU)