White dwarfs: perfect laboratories for understanding non-radial pulsations and revealing secrets on the single degenerate pathway towards Supernova Ia

Abstract

In this work, white dwarf (endpoint of the 95-98% of all stars in the universe) are studied. There are three sub-researches: Firstly, the pulsations occurring in the white dwarf G29-38 and how they can constrain the synthetic modelling of white dwarfs atmospheres in terms of the distribution of the chemical composition over the white dwarf surface. The second is a binary system (GW Librae) which is composed by a pulsating white dwarf that accretes material from a non-degenerate companion, and the evolution of the pulsations in this system is fast (timescales of decades) in contrast of non-binary systems that their evolution lasts million of years. Therefore, systems like GW Librae provide constraints to the asteroseismology. Finally, some systems containing white dwarfs that accrete from non-degenerate companions can carry out information from their past phases, specifically the supernova type Ia progenitors (which are very important in the context of Cosmology). These researches are based on data analysis of spectroscopic data taken with the Hubble space telescope. The methodology relies on the development of synthetic atmospheric models which make use of a novel method for the analysis of the data known as Markov Chain Monte Carlo (MCMC). In addition evolutionary simulations for binary systems are implemented.