Metodologia computacional para o estudo de grupos estelares em movimento

Abstract

[EN] The study of stellar moving groups is closely tied to the study of stellar formation and the determination of stellar age, as well as to the study of the origin and evolution of extrasolar planetary systems. The Hipparcos mission (1989 to 1993) performed high-quality astrometric measurements and resulted in catalogs comprising high-precision stellar positions, parallaxes, and proper motions. With the addition of radial velocities obtained by other means, this made possible the retrograde simulation of the evolution of groups comprising a few tens of stars, aiming to establish whether or not they constitute moving groups as well as where and when they originated. This thesis presents a new computational methodology tailored to the concomitant analysis of thousands of stars, aiming to refine the field’s current understanding of already known groups by enlarging them with the addition of new stars or by removing stars from them. The core of this methodology is the representation of such thousands of stars by the principal components of the data describing them (velocities, magnitudes, spectral types, etc.). Analyzing the resulting representation gives rise to candidate stars that are then subjected to a succession of retrograde simulations for confirmation. As a case study, the methodology was applied to the Beta Pictoris Moving Group , which resulted in proposals to change the current understanding of it.