Estudio de las propiedades fisicas en regiones chocadas en nebulosas planetarias
- Autores: Arjuna Castrillón
- Directores de la Tesis: Jordi José Pont (dir. tes.), Domingo García Senz (codir. tes.)
- Lectura: En la Universitat Politècnica de Catalunya (UPC) ( España ) en 2021
- Idioma: español
- Materias:
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- Resumen
Planetary nebulae play a very important role in the chemical evolution of galaxies since they are responsible for returning nuclear-processed material to the interstellar medium. Observations of planetary nebulae are used to determine the chemical abundances present in the interstellar medium and in all galaxies.
In this study, the properties and characteristics of the small-scale structures present in planetary nebulae are analyzed. The aim of this work is to understand the evolutionary fate of low and intermediate mass stars. Specifically, this work focuses on the study of episodes known as "jets", which are ejected by the central star of the planetary nebula. The presence of collimated bipolar fluxes and point-symmetry morphologies are commonly observed in planetary nebulae, but the physics of such structures is not yet well understood. With this thesis we want to determine the observational properties of some structures present in planetary nebulae, known as FLIER's/LlS (Fast Low Ionization Emission Regions [FLIERsl and Low Ionization Structures [LIS]).
In a first phase, the morphology of a sample of planetary nebulae selected from the HST (Hubble Space Telescope) database is analyzed by applying anisotropic wavelet analysis. Through this analysis, we determined: first, the spatial distribution of the structures of interest (FLIERs/LlS) and their characteristic sizes; second, spectroscopic data with two-dimensional coverage of our sample are obtained. With these data, we can draw maps of physical conditions, such as the excitation and the ionization structure in bow shocks. Through these maps we can show the effects of photoionization due to heating caused by the central star in the areas known as irradiated shocks.
All the analyses carried out on the planetary nebulae considered in this work yield conclusive results on the presence of microstructures. The abrupt changes evidenced in the ratios studied (10 Ill]/Ha, [N Il]/Ha) are a clear indication of the presence of microstructures in the regions of irradiated shocks. From the wavelet analysis, the presence of "knots", "jets", "jet-like" and filaments is evidenced in each of the nebulae considered. Additionally, the one-dimensional profiles present a slight spatial shift in each of the spectral lines considered (10 Ill], [N Il], and Ha), which indicates that the structures are symmetrically located with respect to the central star.
From the analysis of the protoplanetary nebula CR 618, the movements of the lobes measured in two different time periods are quantified. From this, the parameters of the simulation using the hydrodynamic code created by Raga (2000) are set. We obtained encouraging results in the study of this nebula, allowing us to give an explanation to the proper motions and the morphology of the lobes from the well-collimated bipolar ejection and the precession in the axis of their flow.
